Bruise penis after sex.

So i was having doggy sex with my girlfriend
She is slim ,her ass not big since she has small body and she didnt shave too and i was feeling bruising pain but also at some point i felt like i was going against bony structure which caused sharp pain anytime i thrust in .
After i went back home my dick skin was bruised
Took about 5days to heal now am afraid of trying dogyy again with her since she likes it ,that was the very first time we did doggy.I told her i bruised myself maybe due to the friction with hair but didn't tell of the other thing
I like to know if anybody here has had such an experience, any solutions or explanation that may help me.