| This may not be the best thing to do, but it'll work. Deflate the blister with a sterilized needle before you go to bed tonight. Then, before you play bass the next coat that hole area in superglue and massage it until it cures. It will feel kind of weird and annoying, but this will give your finger a hard protective coating. Again, I wouldn't really recommend this except for the time constraint, but it will get the job done. | 
