It is very difficult to remove a tattoo because real tattoos reside deep in the dermis.
In the process of laser tattoo removal, the tattoo pigment absorbs the light from the laser. The absorption of light heats the pigment up very much and this breaks the pigment down. Unfortunately, the heat can damage the skin and leave a permanent scar.
After two years, it is more or less time to give up but before you do, try different approaches. For example, needle the scar three times a week or even every second day for several months. Expose it to the sun immediately after needling (if you can).
You can try some of the substances for repigmentation that are discussed here but I cannot attest their efficacy:
https://http://forums.owndoc.com/dermarolling-microneedling/melanocytes-transfer-for-white-scars-and-hypopigmentation/Consider buying a NB-UVB lamp.
More about it in my reply #13 in this forum thread:
https://http://forums.owndoc.com/dermarolling-microneedling/hypopigmentation-on-chest-before-and-after-needling/