Best mom friend using drugs

Aliana • 20, single & only parent of a handsome 2 year old

Not really sure who I should turn to on this one. Tonight I walked in on my best friend, who has a 2 year old as well, smoking oxycotin. She and her new boyfriend were in her room, I knocked first to give them a warning just in case anything was up. I didn't say anything, I just told her that my son and I were going home for the night.

Not really sure what I should do ?