Some skin conditions occur because the body produces either too much melanin (hyperpigmentation) or too little (hypopigmentation), which is the natural pigment responsible for the colour of our skin.But,Pigmentation of the skin after electroacupuncture (EA) or acupuncture in patients is not well recognised.

Australians have done a research about this,Their case series includes four cases of short-lived or long-term skin pigmentation after EA or acupuncture. Skin pigmentation or dark spots appeared in these four cases........
Skin pigmentation was hardly seen in one case after 14 days, and in another case after 42 days. Pigmentation of the skin could still be seen in one case after 42 days and could still be seen in another case after 2 years, however, in both cases,pigmentation has reduced in size and colour intensity by more than 50%. It is likely that pigmentation of the skin is a specific consequence of needling and may be closely linked to acupuncture dosage regardless of whether stimulation is given manually or by EA.
Reference:Miao EY,Acupunct Med. 2011 Jun;29(2):143-6