Thanks for asking the query,
According to your clinical symptoms i suppose that the above mentioned symptoms are due to the erruption of the wisdom tooth.
This area is usually difficult to clean and leads to bacterial infection leading to inflammation, swelling.
Difficulty in swallowing is due to pain and swelling.
I would suggest you to visit to an Oral Surgeon and get the examination done, take an OPG rdaiograph and plan for the extraction of the tooth.
Take a course of antibiotics and analgesics under the prescription of your Dentist
At home take lukewarm saline and antispetic mouthwash rinses.
Hope this helps out,