small dumbells work great. i had an inflamed rotator cuff when i was 13 and spent the whole summer doing exercises with 3 lb dumbells. at 18, i still only use 5 lbs. for my rotator cuff work. basically you do several variations of what i guess would be considered front raises. i'm sure you can find the techniques online.
but yeah. go out and buy some small weights. i've been using them every day since i did rehab that summer and have never had a problem since. meanwhile i'd definitely suggest taking a few weeks off from throwing altogether.