Hello and welcome to HCM.
I understand your concern.
Redness,warm to touch and itchy over back can be due to impending shingles(
herpes zoster) infection.
-You need to keep a watch if any
fluid filled blisters develop at site,and visit as early as possible to physician ,if in case any blister appear over that area.
If I were your treating doctor,I would recommend
---tablet Acyclovir 200 mg thrice for 3-5 days if it happens to be herpes zoster infection.
- apply calamine lotion locally for soothing.
-local cold compress 3-4 times a day
Second but less likely possibility is
cellulitis.It is accompanied by pain,swelling ,tenderness at the site.If it occurs,it can be treated with a course of antibiotics like
amoxicillin or cephalexin.
-besides,blood glucose test needs to be done to rule out
diabetes mellitus.
Hope this information helps.
Thanks and regards.