I took a shower after i got my back tattoo, as long as your water isnt jetting down on your skin you should be fine And for aftercare, if you dont have someone to help put something on it. Use a flat spatular or syran wrap against a flat surface, put your stuff on it and put your back to it
I have a pretty large back tattoo, and honestly the immediate aftercare was not that difficult, just a long healing process (i was very careful to rinse well and not let conditioner run down my back 😬) but I’m actually having a lot of trouble now putting sunscreen and moisturizer on such a difficult area to reach (but sunscreen and lotion is super important for tattoos, right??)