Everyone's different, but some possible allergy symptoms to PG include excessive dryness, throat or upper respiratory tract irritation/soreness, night sweats, body rash, and .........
I think the most common symptom is a rash or spottiness/blotches.
It could be a number of things though, including flavorings used. If you have the ability, you could try vaping ejuices, eliminating one potential at a time. That way, you'd be able to isolate whatever is causing the issue.