I got bit by a black widow I'm 12 help!?

I got bit by a black widow while crawling under my bed (I was looking for my phone) one crawled on to my shoulder and bit me... Iv been bitten twice by other poisonis spiders so maybe I have an emunity to some extent (I'm hoping) I know I should go to the doctor but I'm going to a party and my mom probobly wouldn't let me go if she knew(I'm 12) so is there some way to get rid of the symptoms( upset stomach fever nausea pain ect.) long enough for me to go to the party?