If you are stage 3 of the hiv symptoms, is it possible w/ medication to go back to stage 2?

Yes, and no: Medically, the answer is yes. People often go from advanced stages of HIV disease to early, healthy stages with treatment. However, from the point of view of your state health department and the cdc, the answer is no. Your official HIV stage is always the lowest stage you've ever had, no matter how well you're doing now. But this is for reporting purposes only and has no medical significance.