I believe those are called hives. It's pretty common. A dose of cetirizine from the pharmacy should clear them up. But just to be safe, go and visit your nearest clinic.

1. You need to undergo Allergy Test to know specifically what is your triggering factor.

2. Usually, from my experience, if came out of sudden without food consumption/insect bite/drugs - usually it caused by dust.

3. You can either buy antihistamine at the local pharmacy OR

4. Go seek doctor attention for detailed examination (BP, HR, lungs auscultation, throat examination) to ensure no issue with your airway/breathing/circulation.
I personally having low threshold for hydrocortisone and Prednisolone, rather than antihistamine alone for my patients.

This is called rashes. I guess you must first find out what you're allergic too, any food that you've consume before rash observed.

It could be due to medication, it could be due to allergic to food.

You definitely can check some allergens by blood test.

Doctor attending you will know how to control the reaction etc etc.

You should be fine.

Hi there! I have something really similar to this... Do you use any meds for it? I would like to get some tips

I have the similar skin rash couple years ago, I have to take Zyrtec every two other days, very itch, can't sleep properly at night some time.

Since I taking apple cider vinegar, the rash is gone. 

Braggs apple cider vinegar - magically cured my skin rash.

Did you diluted it before you drink? Raw honey and ACV in 8oz water is my favorites.

Never try before