Allergie bumps rashes

Patient: So two nights ago i started getting itchy out of no where on my arms. at first i didn’t think anything of it. so the next day i was still kind off itchy but not as much, but later on when the night hit i started getting real itchy again and this time little red bumps/rashes started popping out on my arms and legs almost everywhere on my body. so today i went to the doctor and she told me that i just had an allergic reaction. so she just told me to keep on taking the Benadryl that i was taking since last night, and she subscribed me some pills that were for the itchiness i cant remember the name. so during the day after i had left the doctors i checked my arms and all the rashes/bumps that i had were gone. but later on tonight i got them again and started to get really itchy again. my question is if that’s normal? should i go to the doctor again or what should i do? also if it may help I’ve never been allergic to anything through out my whole life this is the first time this happens to me .

Symptoms: Red bumps/rashes itchiness

Doctor: