Pinterest is great for many things: finding braid inspiration; planning your fantasy wedding; reading motivational fitness quotes; scoping out your next DIY project. But just because you saw it on Pinterest doesn't mean it's a good idea -- in fact, some of those beauty DIYs can seriously damage your skin.

We asked top skin-care experts to weigh in on the biggest Pinterest beauty fails -- and tell us how to make them over -- and salvage our skin.

Image via Pinterest

Why you should skip it: Lemon juice is very acidic, which can burn the skin, says dermatologist Dr. Gary Goldfaden, founder of Goldfaden MD. And, if you do a DIY mask with lemon juice, it can react poorly to UV light, causing a photo-toxic reaction, says Clear Scalp & Hair dermatologist Dr. Francesca Fusco. This usually happens within 24 to 72 hours after exposing your skin to the sun, and can leave you with red blotches, tender skin and even blisters. To make matters worse: Fusco says this reaction can last up to two weeks, and once the redness dies down you're left with greyish-brown patches that hang around for several months.

What you should do instead: Dermatologist Dr. Marina Peredo of Skinfluence NYC recommends mixing Bentonite clay (you can find it in vitamin and natural food stores) with water to create a blackhead-busting mask. It helps draw out skin impurities; use it one to two times per week and you'll start to see your blackheads do a disappearing act.

Why you should skip it: It's easy to see why this DIY treatment is all over Pinterest -- pimples have a tendency to pop up at the most inconvenient time, with no spot treatment readily available. According to Fusco, though, using toothpaste to dry up a pimple overnight is nothing but a myth.

Nearly every dermatologist we spoke to said toothpaste as a pimple treatment is one of the worst things you can do to your skin. It dries the skin around the pimple, not the actual pimple, says dermatologist Jeannette Graf, MD, Assistant Clinical Professor of Dermatology at Mount Sinai Medical Center in New York. "Some varieties of toothpaste can be caustic, and overnight contact can burn skin," adds Fusco. Meaning: Your pimple is going to be a whole lot angrier and inflamed than it already was.

What you should do instead: For those painful, below-the-surface blemishes, resist the urge to squeeze them. Instead, ice them. Graf says this will help constrict the pimple (and ease the throbbing pain.) You can also apply 1 percent hydrocortisone cream to a surprise pimple -- Graf says it's the closest thing to an in-office cortisone shot (which can magically erase cystic acne) as you can get.

Why you should skip it: There's many a coffee grounds face scrub on Pinterest, claiming antioxidant- and glowy-skin benefits. First off, know that because the coffee beans are roasted, the antioxidant benefits are much less, according to Macrene Alexiades-Armenakas, MD, PhD, FAAD and founder of 37 Actives. Plus, she says the abrasive nature of coffee grounds is not something many people's faces will tolerate or benefit from; coffee grounds are too harsh, and cause micro-cuts in the skin. These micro-tears present as irritation, and can even harbor breakout-inducing bacteria. Not exactly the radiant skin you had in mind when you decided to re-purpose this morning's coffee beans.

What you should do instead: If you love the feeling of a physical exfoliant scrubbing away your dead skin cells, Fusco says a better option is to add finely ground sugar to your cleanser -- it melts as you use it, making it a gentler option. It's also a natural source of glycolic acid.

Why you should skip it: Even though baking soda may feel gentler than a physical scrub thanks to its fine texture, it can be extremely irritating to the skin, cautions Goldfaden. Blame its alkaline nature. The surface of your skin should be slightly acidic --typically 4.5-5 on the pH scale -- to protect against pollutants. When the pH of your skin's moisture barrier is disrupted, dryness and breakouts follow.

What you should do instead: Peredo recommends whipping up a mask of papaya and pineapple. Papaya contains a natural alpha-hydroxy acid and pineapple contains exfoliating enzymes; together, they gently resurface the skin with little to no irritation.