noun, noun which may take the genitive case particle 'no'
around the lips; perioral area
Refers to the area surrounding the mouth. Often used in medical, cosmetic, or descriptive contexts. Can function as a noun or as a no-adjective modifying another noun.
I'm concerned about the eczema that appeared around my mouth.
口辺の筋肉を鍛えるトレーニングがある。
There are exercises to train the muscles around the mouth.
Compound of 口 (mouth) and 辺 (vicinity, area). The reading こうへん is the on'yomi for both characters.