After about 5 days, so feels much better. We watched him closely to make sure he wasn't allergic and he is just fine. Problem is, my husband has broken out into a rash and hives, just like if he had taken the medicine. My son and husband play a lot and wrestle around. Is it possible my husband got it from my son's medicine somehow. He didn't drink it or take any of it. But it is possible that he was just around it and the rash and hives are from that?