just wear a small plaster on it during office hours if its a problem.
there is also a super strong skin covering foundation called dermablend if you need to cover it and have it last all day - it is used to cover scars, birthmarks etc.
or a watch?
i expect it depends on whether you have to deal with customers - it may not be what they want to show customers.
if its a private office, i doubt they will mind, as tattoos don't have as much stigma as they used to and are quite common.
(though if it is a skull or says KILL or something they may have a good case, lol)