[NSFW?]Young college coed, think she was rohyped while baby sitting due to suspicious activity, how can she prove it?

[NSFW?] A young woman trying to turn an extra buck watches some kids, girl 7yr, boys 11yr, and 15yr, for a couple her family knows but not well. She has done it before but usually only for the parent’s night out, but not a whole weekend. Usually the oldest boy was over at friends or doing his thing. He resents the fact he wasn’t given the duty to watch his siblings. The whole time he heckled the young lady and made remarks of her that were crude. The night Saturday night, the oldest boy was super nice, even making her a cup of tea, which he was highly enthusiastic that she drink. After putting the girl to bed and enjoying her tea with a movie, she can’t remember anything. She wakes up Sunday morning still on the sofa in a fog, her top is on inside out, and her belt has missed two loops. She asked the younger boy what happened or what has been going on and he is jumpy. The older boy tried to run interference to keep her from asking any questions and his kid brother from answering. She thinks she has been rohyped, slipped a Mickey or worse. Should she check herself medically, and for what? Should she have to pay or should the parents pay the medical bill? What could she do if the older boy closes ranks and intimidates his younger brother not to say anything about what really went on? If she mentions the suspicious activity but nothing is found medically, then what? Would there be traces of rohypnol in her blood after 16 hours? [NSFW?]