You can't force someone to be a parent. I hope dad is taking steps to get custody of his son.

What the heck are you talking about? None of the above shows neglect. When you are a bm, there WILL be times that your kids nails will be too long AND dirty. Kids DO get bruises. A 2nd degree burn is a sunburn! My parents told me not to stick my finger on the cigarette lighter in the car when I was younger and I did it anyway. Does that make them bad parents? No, and I still have the scar on my thumb! The kid happened to have an ear infection...a LOT of kids do. If the ER wasn't alarmed, why should we be? Things to get alarmed about...
"I saw his mother hitting him and it left bruises..."
"He has an unexplained burn that looks like a cigarette burn, and it's infected..."
"When we picked him up, he was screaming in pain and holding his ear, but mom didn't care..."
"He smelled really bad and his mother said he hadn't bathed in a week..."
Is the mom likely a slacker? Probably. But there's a LONG drive from slacker to neglect and/or mentally unfit.

I interpret this to mean the boy is constantly in this sad state of affairs.

Take pictures of everything and keep a log of any verbal communication as well as print-outs of anything on line or written notes.

If you two think there is enough provable neglect then try for custody but be very careful of what almost every attorney will tell you. They're after the case and would advise that one hang nail is enough to get custody when in fact its very difficult get wrench custody away from a mother especially a when the child is that young.

As said above little boys are often dirty, brused, sunburned and yes even second degree burns although that should't happen but once or twice in his growing years. She's on her second chance now with burns. Did the boy say how the burn came to be?

Just a tip...if you do go after custody, you will never have enough damning evidence if you/his dad never verbally address the bm. He has a burn. You should have SOME reason for the burn from bm. Did it match up with the er dr? You MUST give her opportunities to incriminate herself. If they are not co-parenting together and communicating, he will likely never stand a chance at getting custody. If she is crazy, she will incriminate herself, because she thinks what she is doing is okay. It might be okay. SM's and bio-dads tend to read into what's going on instead of obtaining facts and trying to get to the real story. Guilty until proven innocent...isn't that how exes see each other? This entire issue might simply be that bm is a lazy parent, and you are to the other extreme, seeing EVERYthing she does as a mountain instead of a mole hill.

Also, I bet you are cutting his nails before sending him back home. So why would she do it herself? She sends him to your house for manicures eow.

Ok I'm sorry I have to disagree with some of these comments. I worked as a paralegal for 7 years and am now finishing my BA to go to law school. Yes, custody battles are long and very expensive. I have worked family law and I would not recommend putting BM on the defensive, Ask casually but NEVER tip your hand. I'm not sure what state you are in as each one is different. This would be what I would do to build your case:

1. Take him to the doctor EVERY time there is an issue. Remember no documents, no proof!
2. Kids get dirty, fine, but you KNOW when it is neglect. Take pictures of him when you get him in this condition. Make sure they are date stamped. It also would not hurt to have other family members "visiting" when he is dropped off. This will provide you with witnesses.
3. Think HARD about gettin CPS involved. They will not only investigate her but your home as well.
4. If you do want to go ahead, call CPS after you have enough documents to prove there is a concern. Now this is IMPORTANT! CPS is very accustomed to being used as pawns in custody battles. Do not mention in the beginning you even want to change custody, just show them the paperwork and photos and express your concerns. Allow the father to do this. They don't like it when stepmothers jump in because they sometimes view it as an underlying cat fight. Once this is done she will KNOW you were the ones who did it and things may get unpleasant.
5. If you get an attorney ask about the percentages of cases they have won. Then reduce that by a third and you have the truth
6. If you know anyone in town who works in a family law office, paralegal, receptionist or whomever, ask them. They are really the ones who know who the best lawyers are.
7. Lastly, if you cannot afford an attorney you can contact your local court. Ask for the family law division. Then ask the clerk if there is a Pro Se (Pornounced Pro Say) program. This is where you can respresent yourself and they often have a process and forms ready for you to fill out. You will have to pay court costs and parental evaluations.

* I am not an attorney and therefore cannot give legal advice. Please consult an attorney in good standing with your state bar.

I hope this helps you some

do you want this kid full time? if so, call child protective services and have her investigated. it sounds for sure like she'll be found unfit. if you don't want this kid full time, i'd say do what you can when he's with you and pray she cleans herself up!