Girls. should i have let this happen with my friend?

ok this might sound odd, but have a female friend that i have known for years but we're not close and i don't find her attractive. i invited her round for a drink, for a bit of company. anyway, i was really sore on my bum from playing drums with my band the night before. i got tipsy and still felt sore. told her and she asked to see my bum to see if she could help. she told me to take my knickers off, and she put cream on my sore bum. she said i would be better to air my bum and she made me just wear a t'shirt and no knickers. she didn't see the front but i know she would have seen all my bum, when i was in my t'shirt. she didn't touch me in a sexual way apart from putting the cream on my bum.i feel silly for letting her see me like that now though. was she right doing it? and should i have let her?