This sounds like acute urticaria with possible angioedema. Facial/lip swelling can worsen even if breathing is normal now, so please arrange a same-day in-person assessment; a photo alone cannot confirm the cause. Do not start steroids or combine medicines without a clinician reviewing you.
Next Steps
Go to emergency care immediately if swelling involves the tongue or throat, or if you develop breathing/swallowing difficulty, hoarseness, dizziness or faintness. Until reviewed, avoid any new food, medicine or supplement taken before the rash and continue only the antihistamine as directed on its label or by your doctor. You may book a Practo consult with me, but do not delay urgent care.