Every time I try to pick up my uke after not having played it for way too long, I have the same problem. It doesn’t take much for my fingers to blister up – mostly just the strumming finger. This makes it tough to jump back into practice because sometimes I can only play one or two songs before I have to put the uke down due to pain.
I’ve done reading up on it, and I’m not unfamiliar with finger pain and stringed instruments (guitar used to be rough for me). I know that you have to build up calluses in order to play, and that comes with time. But it’s really frustrating when your fretting hand is ready to go and your strumming finger is dead after two times through a song.
I do have a set of felt uke picks, which I picked up to use today in order to continue with the practice. This helped me at least play the song through a few more times and make my practice a bit more worth the effort. But now I have to be careful of my strumming finger (which is bandaged up).
Anyhow, I’m going to try to push on despite this, of course, but it never fails that I have to watch for blisters when I come back to uke. It’s rarely about the fretting fingers and all about the strumming finger.