Dropped can on big toe and it's black at the middle-base of the nail bed. (i know it's blood) what are the chances i'll lose my toenail? also i'm supposed to go to the beach in a month- can i get in the ocean? any risk of infection? thank you?

It is unlikely that you will lose the nail but it will take a months for a new nail to grow from the base & push the bloody undersurface out. That said, the blood underneath the nail acts just like a scab on your skin. Once the active bleeding has stopped, & clot forms, there is very little risk of any infection. There should be no reason that would prevent you from enjoying a dip in the ocean.