There is a myth that skin exfoliation a day or two before waxing and sugaring reduces the chance of ingrown hair. This could be partially true, but in the end, exfoliation may also increase the chance of ingrown hair and other hair removal complications.
Exfoliation removes a very thin layer of dead skin cells. The thickness of the dead skin cell layer (stratum corneum) is 0.01 to 0.04 millimeters. Thus, regular home exfoliation removes only a tiny fraction of this thickness. In the areas of the skin that are more likely to have ingrown hairs, as the pubic area and back, the hair follicles are about 3 millimeters deep inside the skin.
By waxing or sugaring, we remove hair from their roots. It takes at least 10 days to two weeks or more for the newly grown hairs to reach the surface of the skin. When you exfoliate before hair removal, there is no hair stuck inside hair follicles that the exfoliation may release. If exfoliation is to have any benefit, it has to be done at least 10 days to two weeks after hair removal. There is no point in exfoliation before waxing or sugaring.
Even late exfoliation has very insignificant effects on preventing ingrown hairs. Exfoliation may have an effect on preventing or treating ingrown hair when it catches the stuck hair right before emerging from the skin. Reaching only 0.01 millimeters into the surface of the skin, exfoliation can only remove dead skin cells. It is extremely improbable that hair could grow all the length of the hair follicle (3 mm) and get stuck right before emerging from the skin.
Another main cause for ingrown hair is cutting the edge of the opening of the hair follicle. Vigorously removing the hair in the opposite direction of the hair growth cuts the edge of the opening of the hair follicle, something like a paper cut. In the process of healing the cut, the hair follicle may become narrower or closed altogether. Exfoliation cannot reach the closed hair follicle or dilate the narrow hair follicle, as they are in much deeper layers (second layer) of the skin, way down below the dead skin cell layer.
The dead skin cell layer covers the skin like a pad and prevents damage to the skin. By removing the dead skin cell layer, you expose unprotected skin to the forcible removal of hair during waxing and sugaring. This alone can increase the chance of cutting the edge of the hair follicle and thus increase the chance of ingrown hair and other hair removal complications.
Second, to curling hair, the major cause of ingrown hair is inflammation. Inflammation is the swelling inside hair follicles that narrows the hair follicle and deviates newly grown hair to poke into the hair follicle wall and become ingrown. Inflammation is the natural response of the body to trauma to the skin. Exfoliation, either physical or chemical, is considered trauma to the skin and begins the inflammation process. This inflammation can potentially increase the chance of ingrown hair.