This is quite an odd thing to happen immediately after a suntan. Blotching and blemishes are usually occurrences that happen after a prolonged period of time and skin damage; therefore, it can be assumed that the blotching is probably caused by irregular melanin formation.
Melanin is a pigment in the skin secreted by cells called melanocytes. Melanin serves the body by acting as a sunscreen that protects us from the ultraviolet rays of the sun. It does this by converting the ultraviolet light that hits the skin into harmless heat that is dissipated; however, in the process of absorbing ultraviolet radiation, the melanin darkens a bit. This is the mechanism of action and course of events that culminate in a suntan. Another concept to understand here is that not all people are born with an equal amount of melanin production rates. Clearly, evolution has endowed people who live in the tropical belts, and those who draw racial lineage from the tropical belts, with more melanin in the skin. This is because of the amount of Ultraviolet Rays radiation that people in the tropics are exposed to, and over the years, this translated into more melanin in the skin. Away from the tropics, lighter-skinned people are endowed with a reduced melanin production because Ultraviolet Rays radiation is much reduced and not as much of danger. However, when lighter-skinned skin meets Ultraviolet Rays radiation levels – equivalent to the tropical belts – visible changes start to occur. Some of these changes can be sunburn, hyperpigmentation, and melanomas. The types of skin blotching that are connected with sun exposure are age spots and natural melanogenesis. Patchy skin color could also be connected with the onset of vitiligo but the patches would be white in color, and therefore, are not a possibility. Age spots or liver spots are an indication that skin is not able to repair the damage from a suntan. This culminates in small hyperpigmented blemishes, which are concentrated with melanin. Hyperpigmentation itself is caused when the body kicks up its production of melanin in response to excessive sun exposure.
Correcting both of these conditions naturally requires that you use vitamin C – nature’s own bleaching agent. Dice some onions and squeeze the juices from the pieces, then add some freshly squeezed lemon juice and apply this solution over the skin as you would layers of paint. Wait for one layer to dry before applying the next. Do this ritual everyday and follow it up with a cream that contains vitamin E. This reduces the blotching significantly.