If someone spits on me and let's me do something disgusting all in one day and I spit back on them, am I a douche bag?

I've always been taught that spitting on someone is one of the douchiest things you can do, but a kid I know was being a prick to me all day and spit food on me and let me eat food that had my friends spit on it and when I finished told me, so later on I spit on his shirt, I feel like all of my douchey friends will think of me as the biggest douche now. I just need to know, in this one instance, was it okay to spit on him and does it still make me the biggest douche bag ever?