Thanks for the query.
Dont worry it is a coplications of LASERS.
It is matching with heart beat because of pulsation of lips which have rich blood supply
Just apply ice pack you will get relief.
Please meet a dermatologist
if it persists.
Let me know if you have any other doubt.
you can ask a direct question to me on this forum, following the below link.
Wishing you a good health.