Tattoos are a permanent way to do this.
Tattoos are very popular these days, here is "Maa" (Mother) tattooed on a forest guard's arm:
And "krishNA" (the god who wears peacock feathers):
Many tribes use tattoos on their faces too, and we still have many parts of our bodies tattooed, where the tattoo is visible only to us. Here is a lady of the Apatani tribe in Arunachal Pradesh, with her face tattoos (they might signify her tribe.)
However, for temporary adornment, we use other dyes on our skin. One of these is made by grinding the leaves of the Henna (mehendi in Hindi, maruthANi in Tamizh) plant (Lawsonia ermis) into a smooth paste and applying it to one's hand's and feet.
is the wiki entry about mehendi.
It's almost mandatory now for Indian brides to have mehendi patterns on their hands and feet (extending to their arms and legs too, sometimes.) But other festive occasions, and sometimes, just for the fun of it, we have mehendi done:
Mehendi (Lawsonia ermis) leaves and flowers. The flowers are very fragrant and were used in weaving flower-garlands to be worn in the hair, too.
Gloria having mehendi applied
The drying mehendi on the back of Gloria's hands
Sarika Gadikar's mehendi
Mehendi done with a comb
An even more temporary dye is the "AltA".
is the Wiki entry about AltA.
Aradhya's alta-dyed feet
Alta on the foot of a sleeping woman
Both AltA and mehendi are now mixed with artificial dyes, some of which can be very allergenic. About mehendi, the Wiki entry says, "Likely due to the desire for a "tattoo-black" appearance, some people add the synthetic dye p-Phenylenediamine (PPD) to henna to give it a black colour. PPD may cause severe allergic reactions and was voted Allergen of the Year in 2006 by the American Contact Dermatitis Society."
Mehendi is often used as to dye the hair, too. Many of us live to dye!