Two issues can be seen from the images shared.
Firstly, the gum around your wisdom tooth is inflamed that can be the primary reason of your problem here and secondly your second molar is also decayed.
Next Steps
Visit a dental clinic as soon as possible, get a x ray done of both the teeth for proper treatment planning.
Wisdom tooth needs extraction and second molar may need root canal treatment or extraction followed by its replacement which can be confirmed after X ray.
Health Tips
Start with lukewarm saline rinsing for some relief.