Lexapro and OCD

I have Trichotillomania, which is considered a form of OCD, and I'm currently on Lexapro 20mg. I've been on several different kinds of SSRI's but none have seemed to work. I have a check up coming in a few days and I already know that I won't be able to change my medication because my mom wants me to keep on it until summer, when I'll have a break from college to try something else if I need to. I've been on Lexapro about a month or so now and I'm still pulling my hair, more than I have been. I'm also on Wellbutrin-XL 300mg, and I haven't had any crying spells, I feel fine considering that I also have depression. I shouldn't give up hope, right? I mean, there's like 3 more months until summer break and just because I haven't seen any improvement doesn't mean it might not kick in later, right? I just need some encouragement. I hate pulling out my hair. It used to be so short, and now it's chin length! :-) Anybody with any advice, please help me out. Thanks!