Decay of wisdom tooth. For this?

A tooth has 3 layers (enamel, dentin and the pulp). If there is severe pain it is generally suggestive of a cavity(carious lesion) that has penetrated to the pulp and has caused inflammation. Such kind of a lesion is diagnosed by taking an x-ray of the localized area or an x-ray of the entire jaw(which is a better diagnostic tool, as it also allows us to visualize other areas to localize the affected area). If the pulp is involved and there is enough healthy tooth structure in your mouth, a root canal followed by a crown/cap is advised. However if the tooth is a Wisdom molar its generally advised to have the tooth removed as the tooth serves no purpose , its vestigial as is our appendix. So get it extracted if its a wisdom tooth. Some doctors may also advise to treat it but its totally at his discretion.

Get an x-ray/OPG

Dont do hot or cold fomentation