I get red blotchy spots on my chest and upper arms when stressed or upset. i know it is caused mainly by anxiety but is there any remedy for this?

Anxiety & skin rash: Stress and anxiety can trigger or worsen skin conditions such as urticaria (hives). The key is to control your anxiety. Antidepressants can be helpful for preventing acute anxiety attacks. To control your skin rash due to anxiety, you can try cool compresses or take antihistamines. I have found doxepine, an antidepressant with a strong antihistamine effect, to be helpful in stress-induced rash.

Treat anxiety: Red blotches over body is a sign of anxiety but not a common one. If underlying anxiety disorder is treated blotching should stop. There are good medications and several therapies to choose from. See a psychiatrist.