I enjoyed it a lot, the oblivious thing is just fun and not really used much, especially in a serialized fashion.
Regarding feedback, I suppose the more obvious issue is the grammar and use of words, but that's something that will come with experience, it's not a big deal for your first story. As some other advice, while I love the "Oh it's just sunscreen" and other explanations, not everyone has to come up with a whacky excuse and, especially given the meekness of the protagonist, it seems like some (especially the bully types) would be fine just telling him to shut up and mind his own business.
I like where it's going though, a lot.