My question involves criminal law for the state of: Illinois

A friend pled guilty to a sexual offense 10yrs ago at the age of 17 due to many reasons (bad public defender, young and didn't know what was going on, pressure from family to take a shorter sentence. There were alot of things done wrong, which now my friend older now, can look back on like an STD present in alleged victim, but not friend. Also a family member of the alleged victim was dating my friend at the time and recorded victim saying nothing happened without her knowing and that couldn't be used (why would that be?) Case dropped by famil, but forced to testify. On top of that the conviction that shows now is not what was understood then.

1.Is it possible to appeal the plea bargain?
2. Is there a way too find out if the wrong offense might be listed as well?
3. What other things can be done to make some changes or is it too long ago?