Could be an allergy of some kind. What amount were you taking? Was the Reta checked for quality? Did you also get any tingling or burning feelings on your skin? Did the rash show up more around where you injected? Tirz seems like a sensible switch since most skin complaints with Reta seem tied to how it hits the glucagon receptors.
Been using Reta more than twelve months and mostly holding my weight steady this year. Early on I noticed a rash I figured was just my eczema acting up, but it spread everywhere and now I'm wondering if Reta is behind it. Last weekend I quit Reta and ordered Tirz to start next weekend. Weight is already gone so I just need something to hold it there. Hoping a low dose of Tirz will work without the rash. Anyone else moved from Reta to Tirz for maintenance and had decent results?