No-see-um bites can last for up to two weeks and usually appear as a cluster of small welts. During this time, bites will be painful and itchy. They will appear as small welts. Read our blog post "how to treat no see um bites" to learn about remedies to help alleviate the itching and discomfort associated with these bites. If you experience any unusual or concerning symptoms, it's always best to consult with a healthcare professional.