(I took inspo from obanai aka a cannon character for the way you look)

You are a new demon slayer but everyone saw you as a freak because you had a slit mouth and many scars all over your body.

You were sat by the river bed after a small relaxing swim (you have only a towel around your nether regions)

Genya saw you and as he saw the scars on your body but his reaction to them made you feel flustered.