Shula, I also came back from a lengthy "retirement" and had similar problems. Technique came back surprisingly quickly, but it was a couple of years before I could play for hours without suffering for it.

The weakness might be partly inflammation of joints and tendons, in which case a couple of asprin or advil a day will help. (Got that advice from my mother, and it sure helped me.)

I also endorse Elwooddelta's slide-playing suggestion, but go for a Craftsman socket for the slide. Extra weight for the bass end, and they come in sizes! (but the hardware guy looks at you real weird when you try them on)

btw, I say Craftsman because their sockets are the only ones I've found that don't have writing and stuff carved into them deeply enough to interfere with a clean slide sound.

I've heard that squeezing a foam-rubber ball is good exercise for guitar-playing hands. I used to give the steering wheel of my car a good firm "death grip" twice a day. Can't say that it did anything (good) for my driving, but it might have helped get the hand strength back.

But mostly, I think it's just a matter of play when you can, stop when it hurts, and it'll come back in time.