I had internal stitches & wasn't warned about the stinging when you pee. I was advised to pee in the shower or pour a jug of warm water when I did go.
Not sure if that's the same as your stitches. I've been having nightly baths too which have helped. I use tea tree oil but as it just sits on the top of the bath water you need to mix it with a small amount of milk before you pour it in the bath. It can sting a little to start with but I think it's really helping mine to heal x