Pimple scars, blackheads, hair fall.

My acne problem started about 6 months back after I made the mistake of using a steroid cream on my face to fasten the healing process of pimples, further resulting in multiple backheads all over my cheeks. The problem further intensified when I ended up having two pimples which simply wouldn't go. They were pus filled for almost a month, and I also kept popping them. The pus has now healed, however two prominent dark red marks remain, which haven't lightened even a little bit even after the use of salicylic acid and benzoyl peroxide. Also, I've recently been suffering from intense hairfall, especially at the time of shampooing my hair. My hair seems extremely thin now, and simply falls even with the slightest touch. Can I please get proper guidance as to how to deal with these issues. Also just out of curiosity, how long will it take for the scars to fade?