In need of advice

I am a mother of an 8 year old. He currently lives in a different state than I do. He was “released” from school a month prior to it being let out due to putting his hands on others and saying the worst things imaginable to other people. These behaviors have apparently happened all year long, which I didn’t find out about any of it until I heard from his principal. I am currently working on getting full custody of him to get him out of the environment he is in. The thing is, is that I’m going to have to undo everything that has been done. What the heck am I suppose to do!?!? Any advice would help.