sti???

so i gave oral for the 1st time to my boyfriend 3 days ago. im getting a rash on my hands and im getting sick: sore throat and nausea. its probobly just a coinsidence and im getting paranoid. but i know that in the past he had an sti, but he said he got it taken care of, and im still young so theres no way in hell im talking to my mom about this. i think im just gonna wait and see if it gets worse. and if it does im gonna have no choice but to talk to mom about it. so now my anxity is through the roof because my rash on my hand is getting worse and i know that shes gonna point it out and then if it keeps spreading shes gonna wanna take me to the doctor, ugh.