Anyone know how long it takes for Benadryl to kick in for hives? I have had a pretty nasty cold since about Friday and yesterday broke out in hives along my jawline and neck, but only on one side. They don't itch a whole lot but they sure look hideous! I took Benadryl about 4 hours ago and the pharmacist said I should start to see an improvement in 20 minutes to an hour. None yet. Anyone dealt with hives before or know something about this? I have a dr. appointment tomorrow morning, but am hoping I can at least get the hives to go down before then.