Welcome to health care magic.
1.The most possible cause of the swelling in the location mentioned by you could be -
submandibular gland ductal enlargement.
2.This can be due to and obstruction / or gland lesion - sailoadenitis.
3.In this case you may initially advised for a simple facial
massage followed by the investigations if required.
4.The investigation of choice in this case could be
ultrasound to assess weather dilated duct or gland, its extensions and source - presence of any obstruction.
5.IT always good to get examined by a doctor - if the doctor feels to further investigate good, if not required them monitor - if any changes you can take needful actions.
Good luck.
Hope i have answered your query,
any thing to ask ? do not hesitate to ask.
http://doctor.healthcaremagic.com/doctors/dr-ganesh/62888