I had a complete bicep rupture. That's when the bicep rips off the bone completely tearing off the bicep. It happened to me on the distal (lower) part of the bicep. See an orthopedic surgeon that specializes in that area. Don't see an othopedic surgeon that says he does everything from knees, ankles, shoulders and elbows. Jack of all trades isn't who you want to cut you. Big orthopedic practices will have docs that specialize in every area. He will give you an MRI to help him diagnose. My bicep rolled up my arm. He didn't need a MRI to know what happened but he got one anyway.
From what I understand you can actually tear the muscle. I'm not a doc but from what I understand it's worse to detach it from the anchor points. Muscles attach to to bones on each end. You could also have a partial tendon tear instead of a complete rupture. This is an easier repair.
The doctor said it's best to get it repaired quickly before the tissue has a chance to scar. I guess for the tissue that attaches to atrophy and die.
The repair was made for me by screwing two metal anchors into the bone and sewing the tendon to it. In six weeks the tendon will grow and reattach into the bone again. Recovery was very slow for me and it took a lot of work. Five weeks I couldn't curl a 5lbs pound dumbbell without a lot of pain. The good news is that the surgery was a complete success in the end.
I know the bicep isn't a prime mover in benching but it stablizes the tricep. It also is attached from your shoulder to your forearm. You would be surprised how weak you can get from removing one little muscle group like a biceps. I started benching 45lbs when the cast came off and I could do some movement. My arm wouldn't extend completely for a long time.
I hope this helps.