I just went running and got a huge blister. should i leave it or put something on it or what?

Either is fine: You can unroof the blister, or you can allow the skin to slough off on its own. The most important thing is to consider your shoe wear, your socks, and your running technique. If you are getting blisters, something is amiss with one or more of the above. Make sure that you have a good pair of running shoes and socks that are appropriate for your gait. I am a runner, and asics are my favorites.

Leave it alone: I would recommend that you don't not take the skin off the blister. The skin is your best dressing. The fluid in the blister is sterile, by opening it, you can introduce bacteria. If you need to drain it for relief, do it sterilely, then place a compression dressing on it. It will impove over several days to weeks. Dr l.