Thanks for query on HCM.
Itchy.red spots all over the body is most likely due to some allergic episode called urticaria
You have to take anti allergic medicines like levocetrizin,fexofenedin.
In severe cases oral steroid
is also indicated.
Intra muscular injection of pheniramine
maleat will be helpful to get fast recovery.Local application of calamine
lotion is also advisable.
You will get cure within next 3 to 5 days with this medicines.
Take proper local care.
Try to find out the the cause of allergy so you can prevent it recurrent episodes.
Consult your physician for better guidance and proper medical management.