Hi..
Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concern..
As per your complain a blister on the
upper lip that has grown in size and has occurred within a night seems to be due to either any
bug bite that has led to infection or can also be due to bacterial infection over the lip..
It can also be due to
allergic reaction in case if you have used any new lip cosmetic or shared lip products with other individuals..
But it no where looks like Herpes causing
cold sore..
I would suggest you to clean the area with antiseptic solution and apply antibiotic ointment over it..
You can also apply steroid ointment..
Do cool compresses..
Maintain cleanliness and avoid touching it repeatedly as it can cause spread of infection..
In case if it does not resolve in a week
consult a Dermatologist and get evaluated..
Hope this information helps..
Thanks and regards.
Dr.Honey Nandwani Arora..