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In exactly which part of the lower lip?
Does she have any eruption in the face?
Did she have any trauma or bite?
There can be a few possibilities.
A mucus cyst is possible.
It is painless & benign.
If she bites her lip accidentally then there can be a collection of blood.
On exposure to sun there can be a rash.
But there should be rash in other parts of the body.
Herpes or fever blister can cause red bump but it does not look like herpes.
Herpes is usually painful & by 2 weeks there would be some change.
It does not seem to be anything worrisome.
But as it is persisting, I would suggest to get it checked by her doctor.
Though there is no direct relation but stress can be a factor.
You are always welcome.
You can wait for another 1-2 weeks.
Please keep the lip moist.
If she develops any pain or if it continues to enlarge then you should take her to doctor.
If there’s anything else I can do, please let me know
You are again welcome.
We have discussed in detail. If you need any more help, you can come back & ask after rating also.