Thanks for writing to us.
It seems you have developed post inflammatory hyperpigmentation
of the lips secondary to the blister on lips. To treat the same apply a mild steroid cream over the spot in night and Kojic acid
and vitamin c
based cream twice in a day. Also use a lip balm with sun protection factor. Hopefully your pigmentation eill reduce. You may also take few sessions of mild spot chemical peels
to reduce the pigmentation.
Hope that helps. Take care