Can you catch something from using a microwave that had a used band aid inside of it?

Germs require a favorable environment to survive. I can't imagine any germ that was subjected to microwaves for a minutes surviving long enough to infect anyone with anything. The waves heat them up and explode them.

No. Microwaves would kill any germs on the band-aid. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs.