bruise, contusion
痏 centers on physical injury to the body's surface: a bruise or contusion caused by impact.
痏 combines the sickness radical 疒 with 有, which likely contributes a phonetic element. The exact historical development is uncertain.
The sickness enclosure 疒 wraps around 有, like a bruise forming under the skin. Picture a visible contusion contained within the body's surface.
For イ, imagine an 'eek' of pain when a bruise is touched: 'eek' -> イ, and the sore spot throbs inside the 疒 enclosure.