Yes, these can be caused by your stress and not bathing. You say they are just pumps not a rash, which can develop as well from stress.
Instead of avoiding a bath when under stress, take many long relaxing tub bathes to help relieve stress. Scrub every inch with a wash cloth to stop all other skin bumps. Then cream to prevent drying skin.
The only part that might have come from sex is chaffing that helped dry your skin to a point the natural oil could not escape. I am still referencing bumps only.. if you have other symptoms this may be different.