Masks should also be washed regularly to reduce the risk of exposure to germs and bacteria. Bacteria, virus, dust and allergens can lead to a sore throat. These particles accumulate on the mask when you use them without washing. The tiny particles pass on to the throat, causing irritation. People with weak immunity and allergic to dust or pollen particles are prone to this.

from Times of India https://timesofindia.indiatimes.com/life-style/health-fitness/health-news/why-are-some-people-getting-a-sore-throat-from-wearing-a-mask/articleshow/78320898.cms