Hi April, I have needed to use 5FU on my lips, medication that is similar to Efudex.
You are right that the lips are very sensitive.
Due to that reason, I was unable to use the cream for as long as I have used it on other facial areas.
I used the cream at bedtime to avoid licking my lips.
When I applied the cream too close to my inner lips, to remove any excess, I would use a gloved finger, (covered with a gauze pad), in my mouth and then withdraw it through pursed lips.
If painful, I would use cool compresses as needed.
Despite the shorter time used, the 5FU was quite effective, thank heavens!
I wish you the very best of luck, even better than my experience!
Please keep me in the loop on how you are doing.
Thanks, Elizabeth Lebowitz - SkinCancer.net - Site Moderator