Be honest: When’s the last time you switched out the razor in your gym bag? If it’s old, the blade you’re dragging across your face could be contaminated with bacteria and fungus. If the razor is dull, it pulls at (rather than cuts) the hairs, notes Dover. This causes razor burn and inflames hair follicles, leading to red, pimple-like bumps—pretty much the opposite of the clean-shaven look you were going for.
Fix it: Change your gym-bag razor as often as you would your at-home version. After you shave, let it air-dry instead of stuffing it back in your bag alongside your sweaty shorts.