As you gain weight and your skin stretches your tattoo will stretch with it. Depending on how much weight you gain this can distort the tattoo. Tattoos on areas like the stomach and thigh will distort more than areas like the back. If you lose the weight your tattoo will return to its original size.
You keep cling film on a tattoo for the minimum amount of time possible. It’s there to keep your tattoo safe and clean until you get home and have chance to start your aftercare regime. If you keep the cling film on you run the risk of an infection starting in the damp warm conditions under it.
Weigh loss of a few pounds won’t have affect your tattoo. If you lose a significant amount of weight it will change the tattoo and you may lose small details. If you have a lot to lose it may be wise to wait. Location of the tattoo also makes a big difference to how it will look after weight loss.