Can you tell me some medicine for my bad dust allergy?

See an allergist: I assume you mean house dust mites. These are tiny insects that like humidity higher than 50%. They live on bedding, carpeting furniture and are increased also with pets. Removing carpets, buying a dehumidifier to ensure low humidity, encasing pillows and mattresses in mite-proof cases, washing bed linen in hot water strong detergent may help. Allergy medication will help. If not, see an allergist.

Dust mite cover: Using dust mite cover or encasing for your mattress and pillows, wash the linen with hot water every week would kill the mites and decrease the amount of dust mite allergy. If OTC medications do not control your symptoms, you should see an allergist. There are several treatment options for dust mite allergy.