Well, usually mumps doesnt present with gum swelling. Usial presentation is with parotid gland swelling. Also it is highly uncommon in adulthood. And when it occurs in adulthood, it can be accompanied with testicular swelling as well.
Next Steps
Consult an ENT specialist or a general physician in a hospital. even after swelling has subsided, if u continue to have fever then u may need to undergo blood tests