hello and welcome to HCM forum,
i am glad you posted your query, first of all i would like to inform you that the lump which is now formed on the inner surface of your lower lip, is nothing but a fibrosed,healed tissue. you have not mentioned about its consistency or if their is pain associated with it, i assume it is painless and firm in consistency.
i would recommend you to avoid biting over it, as healing will be delayed, if you bother it too much.
use an antibacterial (betadine
) mouth wash twice/day ,practice this for a week.
but , even if does not disappear after a week, then kindly visit your dentist
for a check up.,
i hope i answered you query,
i wish you good health.