Aw mama, 28 weeks ka pa lang kaya super sensitive ang gums mo right now dahil sa pregnancy hormones, common talaga yan, pero ang swelling ng cheek at infection signs mo parang need na ng doctor check talaga, hindi lang self-care na. The salt water and Sensodyne are good, pero if it's been hurting na ganyan and the swelling spread to your cheek, baka may infection na or lodged something sa gums mo na kailangan tanggalin ng dentist mismo, better safe than sorry, especially pregnant ka pa. I'd really suggest you see your OB or a dentist ASAP kasi kung infected yan and left untreated, pwede ring mag-affect sa pregnancy; plus it's just causing you too much pain to function, so walang punto maghintay pa. Hoping you feel better soon, mama!