Don't scratch! I know it's totally killing you, but don't do it! I have found the bio oil works okay, but I use Burts Bees Mama Belly Butter and I love it!
Don't scratch it it causes stretch marks
Aside from typical lotion, or vaseline, I'm not sure what else might be helpful. You might ask your doctor to see if there might even be something they'd prescribe to give you relief. Pregnancy can really dry your skin out, or at least make you very itchy and uncomfortable! Goodluck finding something!
I use shea butter to help me. It helps alot