Thanks, DBasler. Yes, we have different issues, as you say.
I had an MRI done at the time, and the tear was very much visible. 'Rest and let it heal' was the consensus. And I really did.
One doc suggested that I get on an ellipsis machine on a regular basis, w/very low but deliberate resistance on the injured arm, plenty of hydration, and get a good blood flow going, in a very gradual 'progressive resistance' kind of way wrt the bi. That actually helped, though it may sound odd.
It's probably time to get another MRI done, though. To see what things look like now.
The tissue has healed enough that it looks like a 'normal' bicep again, and it's able to handle normal, everyday tasks, and some resistance at the gym.
Problem is that as soon as I try to push the envelope with stuff like rows or curls in any serious way, it threatens to give in.
I guess I'll have to stick with high reps on machines and some careful DB work for the unforeseeable future. Keeping the blood flow going, if not much else.
I actually had a partial tear in my right hamstring when I was in my early 20's (not nearly as deep, though, but still), and that healed rather quickly. Not going to say that I'm 'old' at 43 or anything, but I kinda see a connection there