sudden allergy to alcohol?

i’m 20F, i’ve been drinking alcohol since i was 17. i used to drink pretty heavily when i was 18 (first year of uni), but it became unhealthy so i’ve been drinking only once per week, having maybe 2-3 drinks for the past 6 months or so.

i’ve been taking zoloft for 4 years, it gives me a lower tolerance but i never had any sort of allergy symptoms. a few weeks ago i got a really bad rash on my shoulders after having 1 margarita. it went away after about an hour and i knew alcohol flush is a common thing so i didn’t think much of it.

last night my friend and i shared 2 bottles of wine and after an hour my hands, shoulders, arms and legs got red splotches on them. not itchy, just hot.

i’m not asian but i know alcohol flush is common, however this is a new symptom to me and i find it strange that it happened randomly after drinking only wine. i read that sudden changes in alcohol reaction can be a sign of an underlying condition like cancer so i don’t know if i should ignore it or wait to see if it happens again or call my doctor.