The red swollen raised rash on the arm with the appearance in the photo looks like a local allergic reaction to an insect bite â likely a mosquito or ant. This type of reaction is common and causes redness, swelling, and itching at the site. It usually resolves on its own in a few days.
Next Steps
Apply an ice pack or cold compress to reduce swelling, and avoid scratching. An antihistamine tablet can help with itching and reduce the reaction faster. If the swelling spreads, you develop fever, or red streaks appear, see a doctor promptly. Please consult me directly on Practo for a detailed evaluation.