I tried it for stretch marks, and it's completely useless. I do sort of control experiments on myself. When I get a new product, I only use it on one side of the body for a month. Bio-Oil makes skin moist and more plump. For some people, that would reduce the appearance of scars. But you probably have to keep using it for the result. If you have oily skin, definitely break out hazard.
If your scars are rough, you might need salicylic acid or retinol to increase cell turnover. (Your skin will become sensitive, so apply sunscreen as well.) If it is hyper-pigmentation you are concerned, you will also need a whitener such as topical vitamin c, or arbutin.
Have you read "Skin Type Solution" by Dr. Leslie Baumann? Should be able to find it at your local library. The best book for skin care I've ever read. A must read!
Totally feel your pain. I used to have lots of acne scars. Now that they are all gone, I'm fighting wrinkles...