Does Your Skin Have to Be Pre-treated for a Chemical Peel?

These can be administered with little to no prep but Retin-A is always a reasonable adjunct. Avoidance of sun prior and subsequent to the treatment is important.

Generally for light peels such as glycolic and salicylic acid no pre-treatment prep of the skin is necessary.

Pretreating the skin (usually with retin-A) before peels accomplishes two things: first it thins the epidermis and allows the peel to penetrate deeper and more evenly, and second it suppresses melanocyte pigment production so that the skin is less likely to hyperpigment in response to the peel.  The first part of pretreatment (thinning the epidermis) can be accomplished mechanically by dermaplaning (essentially shaving) the skin) and is integrated into immediate peels in many practices.  This allows for a more even and penetrating peel.  The bigger concern is hyperpigmentation.  Lighter peels such as glycolic, salicylate or light TCA peels don't penetrate deeply enough to warrant pre-treatment since they don't get down to the melanocytes.  Deepr peels however (deep TCA, lasers etc.) can stimulate melaocytes and may benefit from pretreatment. 

For a light peel with glycolic or salicylic acid, you do not need to really prep.   As said before, Retin-A can be used sometimes to augment the effect of the peel. 

No, you do not have to do anything prior to a chemical peel.  With that being said, it also depends on what your goals.  If you have a lot of sun damage, I would recommend starting a "skin brightening" regimen approximately 4 weeks prior to peel.  3 weeks on and stop 1 week before.  This will help prep your skin so that the chemical peel can penetrate.

Again, there is no right way or wrong way.  I would recommend seeing a paramedical aesthetician so that she may give you a full skin analysis and her recommendations.