Receding hairline, thinning, and Rogaine

I'm 27 and I'm worried about my thinning and slightly receding hairline. The problems started about 2 and a half years ago and thats when I started using Rogaine Foam. Its not ridiculously bad right now, but the thinning (all over the top where the Rogain is applied) is noticeable in the right light (see attached pic). So I'm not sure if the Rogaine is working. I'm afraid that if I stop using it, my hair will fall out faster.

I'm wondering now if the Rogaine isn't working and if it has somehow accelerated my hair loss/thinning through unnecessary use (Did I jump the gun in starting to use it when I really didn't need to?). If so, and I stop using it, will my hair go back to normal? Or have I permanently damaged the follicles and made myself dependent on the drug?