red sores on nose
齄 refers to red sores or inflammation on the nose, a specific skin condition affecting the nasal area.
齄 combines 鼻 (nose) with 查, which likely contributes a phonetic element. The character is used for a specific nasal skin condition.
The left side is 鼻 (nose), and the right side 查 looks like an inflamed, bumpy surface. Picture red sores breaking out on the nose.
For シャ, imagine a shaman (シャーマン) treating the red sores on the nose with a healing ritual: shaman -> シャ.