I don't know what bug bit me! The red envelope is so itchy!

According to your description, it should be bitten by a bug.

Bedbugs, some people call them bedbugs, suck human blood at night. They live in the crevices of beds, wooden furniture, ceilings, floors and walls. They usually move at night and lurk in the above places during the day. After people are bitten by bedbugs, their skin often itches. Allergic people have obvious irritation after being bitten, and the wound often appears red, swollen and itchy. If it is scratched, it will often cause bacterial infection. Bedbugs can spread many diseases, such as relapsing fever, leprosy, plague, polio, tuberculosis, trypanosomiasis, oriental furuncle, kala-azar and so on.

Bedbugs may exist in families, hotels, hospitals, nursing homes, cinemas, schools and so on. Because bedbugs have strong adhesion ability, they can be attached to luggage, travel bags, shoes and so on. And spread with the circulation of these objects. Generally speaking, bedbugs can only be eliminated by artificial capture, boiling water, high temperature exposure and strong chemicals. But the most effective and simple way is to cover the mattress completely, so that bedbugs can't enter the mattress to parasitize, and at the same time, bedbugs in the mattress can't climb out of bed to bite the human body, cut off its food chain, and then destroy it! The most professional brand in the United States is a bedding protection brand called PROTECT A BED, which is called Bedding Castle in Chinese. It seems that it has just been listed in China. You can look for it.