Rash from online thrifting! Help please

So I’ve developed this rash after trying on a couple linen tops I bought. It’s spread across my forearm and elbow and is really itchy and I have just gone down a rabbit hole of how some people have even gotten bed bugs ! Please I online thrifted a bunch of other clothes as well and now I am scared they are dormant in the clothes. What if they are dormant and not visible and just spreading in the apartment ?!?

Just for context, I had a t shirt on when I tried the cardigans on , NOT wore them just tried on. But they did cover my full arm