If you forgot to apply sunscreen before spending the day outside or didn't reapply SPF often during a day at the beach, you could end up paying the price with a sunburn. How long will the sunburn last and when will the redness, pain and chapped skin finally disappear?

"A sunburn, like a tan, is the body's defense mechanism against the sun's harmful ultraviolet (UV) rays," dermatologist Debra Jaliman told Health. When the skin is exposed to ultraviolet light, the body produces melanin, a dark pigment produced by skin cells called melanocytes. Melanin is designed to protect the skin and how much a person produces depends on genetics. When people who produce less melanin are overexposed to UV rays, it causes DNA damage in the top layers of skin cells – resulting in sunburn.

How long a sunburn lasts depends on how severe the burn is, dermatologist Rhonda Q. Klein told Health. "In three to five days, the redness and pain may be gone. But if you have a more severe, blistering burn, it can last up to 10 days," she says.

Sunburn pain usually begins two to six hours after excessive sun exposure and peaks within 24 hours. If you have a more serious sunburn, the skin may blister and peel. Blisters usually appear between 6 and 24 hours after sun exposure, but sometimes it takes longer.

Scaly skin is part of the healing process after a sunburn and tends to start after about three days. This process ends when the skin is completely healed, which can take several weeks in cases of severe sunburn. Resist the temptation to touch the injured area.

Sunburn dehydrates you, so it's important to drink plenty of water. Hydrated skin will heal faster. 

First of all, it's good to know that you should:
- invest in a sun protection cream, where the minimum protection factors (SPF) must be 30;
- apply cream 20-30 minutes before being exposed to the sun;
- apply protective cream every 2 hours;
- avoid staying in the sun during hot hours;
- cover yourself with a scarf, hat and glasses.

If you didn't follow the tips above and end up with red skin that burns terribly, soothe the pain with an anti-inflammatory that eases the burning and itching. Stay out of the sun until the skin calms down.

You can also use products you have at home such as yogurt or cold milk, aloe, wine, egg white + honey, potatoes (cut into thin slices and apply them to the burned skin), tea bags.