So I've been on Epiduo for about 2.5 months and an oral antibiotic for about 6 weeks. My active inflammation and acne have cleared up dramatically, but I'm afraid my forehead scarring is over the top. I don't understand it either... I had papules, pustules, whiteheads, comeadones, and the like, but no nodules or cysts. I don't understand why my scarring is so extreme. Any advice would be much appreciated!
To me, it looks like you have a lot of red marks, but no or few 'real' (atrophic) scarring. 
That is pretty normal and almost every acne sufferer has to experience post-acne marks regularly.
The good thing is, it will go away on its own within 6-12 months, depending on how good your wound healing is.
But you can speed up the healing process quite bit by taking zinc (15-20mg a day) and vitamin c, so it won't take that much time. On top of that, it is beneficial to eat healthy so that your skin gets all the vitamins it needs to renew itself and drink lots of water.
And don't worry too much, it will eventually go away ! And of course, the best way to prevent getting these red marks is not to get pimples causing these, so you're on on the right track!