My Boeboe gets hives easily, hers also usually just last a day or two, and then they go away. I thought she got them from flea bite but I'm not so sure anymore... it's sometimes really hard to figure out allergic reactions
It could be something he ate maybe? When he got Benadryl it helped but when the medicine left his system the hives came back?
Keep an eye on him so he doesn't get trouble breathing<3