Ok...Taylor gets a tattoo when she is with the new guy brock. If you look closely she has it throughout the movie but the very end, the prom scene....wonder where it went!!!
While thats true, for this to not be a slipup they would have had to make mention of the tattoo removal.
Anyways tattoo removal is a time consuming and painful process, especially at the time, it would have taken many sessions (many months worth) to have the tattoo removed. Unless she just let someone take a belt sander to the area...