Puncture the blister, drain, let dry. Do it at bedtime so it has a few hours to toughen up a bit before you play again. Use a string lubricant (e.g. FingerEase) until callouses develop. IME, playing flats or rounds doesn't matter. It's really just a matter of time. Avoid playing "Locomotive Breath" by Jethro Tull.
Super glue is great for cracked skin around fingernails for me.
The Bar Band Bassman
The Bar Band Bassman