Hi
Yes if your molar cavity is deep enough to reach to the tooth pulp, then yes it can cause infection and swelling in the adjacent area. It will have to be clinically diagnosed with a visual check up and a xray.
Next Steps
You should keep doing warm salt water rinses to subside a little bit of the swelling.
Health Tips
Avoid eating/chewing from that side. And get a visual check up done whenever possible by your nearest dentist.