Hello,
These marks can be insect bite,contact dermatitis,hives or dermatitis.
The mainstay of treatment is antihistamine and non-sedating antihistamines such as Cetirizine(Zyrtec) or Loratadine(Claritin) may be needed to get symptom relief. Sedating antihistamines such as Chlorphenamine(Benadryl)is used at night to get urticaria control. Short courses of oral cortisone or steroids are taken for short periods (one to three days) to settle more severe symptoms.
You may take Vitamin C along with the prescribed treatment. Vitamin C is a general anti-allergy supplement. It helps stabilize mast cells so they are less likely to release histamine.Also apply calamine lotion and mild steroid cream on the rash.
If the symptoms persist then pls consult a dermatologist.
Hope it helps. Take care and pls do keep me posted on how you are doing or if you have any additional queries.Kind regards.
Application of caladryl should help to what look like bugbites in this pic.