"Holiday" is also slang for the white, or lighter marks found on tattoos.
Holidays come from poor care of a newborn piece of work, which means it was either picked at, not moisturized, let out to play in the sun, or otherwise abused.
The notion here is based on how a tattoo actually works... When ink is injected into your system, your system tries to reject it. Thats why those scabs are coloured. When you pick at them, you actually pull some of the ink out from under the skin.
The only way to fix a holiday is with more ink.