This. OP I HIGHLY suggest getting a rape kit done which would mean not showering/messing with your vagina. It's extremely important that you do, if you decided not to then pursuing or doing anything about this in the future will be really difficult.
As for STDs, the only thing you could potentially prevent at this point is HIV which is why you need to go to the doctor as soon as humanly possible to get put on medication for it (PrEP). PrEP is time sensitive, and HIV is a lifelong disease. Any other STDs are unpreventable at this point assuming you got them.
TLDR; pls see doctor, and im sorry that this happened to you. you didnt deserve it and its not your fault