Hello and thank you for your question,
I am sorry you didn't get an answer right away.
Can you tell me if this lump is movable under neath the skin? Does it feel boggy or hard if you press on it? Does it hurt if you press on it?
Thanks for your reply.
Looking at the picture, it looks more like a cyst (called epidermal cyst) which suddenly developed under the skin. Another possibility could be a blocked salivary gland which caused some back up of saliva creating a lump. This doesn't look like skin cancer at all because it is underneath the skin - all types of skin cancers are located on top of the skin. It is also unlikely to be a lymph node because it is not a location where lymph nodes are located.
You can try to apply hot/warm compresses to it but if it doesn't dissolve on its own or continues to get bigger, you will need to get it surgically removed. Because of its location, you will probably get best cosmetic results seeing a plastic surgeon although a dermatologist or a general surgeon will also be able to remove it.
Removal is a very simple in-office procedure.
I don't think you have anything to worry about as it will not affect your overall health but because it is uncomfortable (both physically and emotionally for you), I would recommend excision.
I hope this answers your question. Please let me know if you have any other questions.
If you are satisfied with the answer, please do click 'Accept' button so that I may get credit for my work.
Best wishes and good luck,
Yes, cyst can appear overnight. Blocked gland will also appear overnight and they may be painful but not always.
The reason you feel uncomfortable (especially when smiling) is because your skin is stretched in a way it is not used to being stretched so it causes a pulling sensation.
Hope this helps. Let me know if you have any other questions. I will be happy to assist you further. If I answered your questions, please do click 'Accept' button so that I may get credit for my work.