I Have Two Red Marks That Remind Me Of Bite

I have two red marks that remind me of bite marks that have turned into whelps. I usually swell when I get mosquito bites and these two marks have swollen up like that. The only difference is both of these areas are warm to touch. I was pulling samples out of a cabinet that had spider webs and things of that nature the day these marks showed up. I take the benadryl and it doesn't itch as bad but I did feel a pain sensation when the hot water in the shower hit it. Also depending on how my arm is flexed i see tiny little indents all throughout the marks. Do you know what this may be?