How effective is tattoo removal? Will it hurt my skin?

Very effective. Now a days we have very powerful, safe and effective Q-switched lasers that are able to remove tattoos with a few treatments with minimal discomfort. It actually hurts way more to get the tattoo than to have it removed. The key to success and minimal pain is to go to a board certified dermatologist who has completed a fellowship training in the use of lasers.
Depends on color. Laser tattoo removal is the safest and most effective method for removing tattoos but effectiveness largely determined by the color/pigment of tattoo used. Black is the easiest color to remove. Green is the most difficult. Red, yellow, orange, exotic, vibrant or fluorescent colors, light or flesh-toned also difficult. Possible to have lightening of the skin, scarring, or residual pigment left.