Swelling
noun
You know that 腫れる means "to swell," and this is the noun version: swelling.
The reading is the same as the one you learned with the kanji and with 腫れる, so you should be alright here.
腫れと痛みがひどいんです。
The swelling and pain are severe.
腫れが出てきたら、冷やしてください。
If swelling develops, please ice the area.
腫れが目立ってきましたね。
The swelling's gotten noticeable, hasn't it?
腫れを抑える薬を出しておきますね。
I'll prescribe you some medicine to reduce the swelling.