I'd go a month of no curls, then start slow and don't go back to current weight for at least another month. The little bit of extra time rest is infinitely shorter than the rest required if you really injure it or it flares up again because you didn't rest it enough. Fortunately this should be easy because curls are useless (/hate)Have a slight case of what I believe is biceps tendonosis (although, 2 weeks ago it was so bad I couldn't even lift the bar on my last set of curls). I took last week off altogether, and this week I did a very light chest/biceps day (115 lb bench 3x10, 45 lb ez bar curl 3x10, 30 lb cable chest press 3x10, and 20 lb dumbbell hammer curls 3x10) and felt ok. The last two sets of hammer curls I started to feel some pain again. But yesterday I was doing some rowing and the pain started coming back a bit stronger.
My shoulder is doing much better. I've started press (75lbs+10/week) and bench (95lbs+10/week) as of a couple weeks ago. Super boring. On press I'm making sure I squeeze my traps toward the top so my shoulder joint has plenty of space. I noticed that it is difficult to squeeze my traps at the top unless I stretch out my back first. Now I wonder if having tight back muscles was preventing the scapula from moving and caused the whole impingement problem in the first place. Regardless, I'm doing more back stretching by just hanging on the pullup bar and whatnot. All my other lifts are approaching my previous PRs after taking almost 2 months of going lighter as a precaution.
The only remaining problem is bench still feels weird in my shoulder joint. It's the same feeling as before it was hurt, though much less. I'm going to try bench with some dumbbells and see if that makes a difference, but if not, I'm not sure if I should keep at it with light weights or take another few weeks off completely?
edit: also, I think the low bar back squats was fucking with my shoulder a lot also. It's a pretty big stretch for me to reach like that, having inflexible shoulders. I don't want to stop those because they've been miraculous for my legs, so I dropped it to just 1 workout a week, then subbed bulgarian split squats and box jumps (on power day, to complement cleans) on the other days. I'm thinking about canning the box jumps (because I don't have a weight vest and I have hops like a black man so the height of the box is getting a little ridiculous) and doing dynamic effort (power) sets with high bar squats, which would be easier on the shoulder. /diary