Hi,
As per your query you have symptoms of red welt and
white spots on the lower back. Well, there can be many reasons for symptoms you mention in the query like allergic reactions, insect stings, sunlight exposure, side effects of medications and
allergy from some common foods nuts, chocolate, fish, tomatoes, eggs, fresh berries, and milk.
I would suggest you avoid trigger factors given above, take over the counter antihistamines like zyrtec and apply cold compresses on welts to reduce inflammation and
redness. If the condition doesn't get better then
consult a dermatologist for proper examination and start treatment accordingly. Also, keep yourself hydrated.
Hope I have answered your query. Let me know if I can assist you further.
Regards,
Dr. Harry Maheshwari,
Dentist