Seems like it usually is a 7 - 10 day thing, but my husbands lasted almost 3 weeks once. I'm here looking for info on children. My 10 yr old son just broke out on his face and both eyes, after having something blown into one eye while playing outside on a windy day. No blisters just swelling and itching so far, but it only took about 12 hrs to start after his exposure. So far I like the homeopathic stuff myself, and applying cool water or cold packs seems to feel good to him.
It's 4:30 am and after being up all night trying to keep him from scratching, a luke warm shower, a dose of Apis mellifica 30C (homeopathic medicine) and an ice pack, finally has him sleeping. I was trying Benedryl and it wasn't relieving the itching for him. Whew, what a night! Hope you find quick relief.