Update: Its seems my fingers remembered what it was like in the old days when I gigged regularly. Leaving the blisters alone for a couple of days, they hardened into nice callouses and now I'm able to play again as long as I'm careful not to over-do it and back off when I feel pain. All is well.

Thanks for all the helpful suggestions, everyone!

By the way, I'm glad I resisted the temptation to break the blister. That seems to have made all the difference.