a medicinal herb, to cauterize
薰 centers on a fragrant medicinal herb and the act of using its smoke or heat to treat wounds, hence cauterizing. The meanings connect through the idea of applying a scented plant for healing.
薰 combines 艹 (grass/plant) with 熏, which likely contributes both sound and the idea of smoke or fragrance. The character originally referred to a fragrant herb used for fumigation or cauterization.
The top 艹 is a plant, and the bottom 熏 looks like smoke rising from a fire. Picture a medicinal herb being burned to produce healing smoke that cauterizes a wound.
For クン, imagine a fragrant herb called 'coon' (like raccoon) that smells so strong it can cauterize: coon -> クン, and the herb's smoke heals.