Hello Jade .....
I'm from Illinois, and I would say a school counselor would be the best place to start - if the child is of at least middle school age. The counselor would know the alternatives of what can be done - and who to see.
I think little medical attention could be gotten thru the school itself though. If there was a breach of parental responsibilities, there should be several options - none very pleasant on or for the child .... but things that do need to be done.
If the lack of parental direction to medical help is religious associated, there could be problems .... but the school counselor is still likely the best place to start.
Good luck.
Rob & Gizmo