A: What's the matter with you?

你怎么啦?

B: This tooth hurts.

这颗牙疼。

A: Let me have a look.

让我看看。

A: Your tooth has an abscess.

你的牙齿有脓肿。

B: My gum also hurts me.

我的牙龈也疼。

A: It seems that there is an infection.

似乎是感染。