After the peeling of sun poisoning how long till skin becomes normal again and are able to tan possibly or just be able to be in the sun?

See below. Depending on how severe the burn was it may take several days to a week and longer for a severe burn. Although the skin may return to looking normal, it has been damaged and repeated sunburn effect is cumulative and can lead to skin cancer. It's extremely important to use at sunscreen with SPF of 50 or more, even when it is cloudy or hazy outdoors.