Yes, with dosage according to weight, Benadryl is prescribed as a light tranquilizer and can relieve skin irritation.
Depends on whether they are male or female. Respectfully you would call them Mr. Or Mrs.
There could be a number of causes ranging from a bad valve in the shower to calcium build up in the pipes leading to the valve in the shower.
While raising two daughters in south Texas, we kept a bottle of Bactine spray in the house. Fire ant bites were pretty regular and the spray helped deaden the pain while the bodies immune system fought the poison. Unless there is some serious allergic reaction this should work for you as well.