Hi My Name Is Neil , I Am 50 Years

Hi my name is Neil , I am 50 years old this year and every now and then at any time my neck and face suddenly goes really hot and rashey but not raised rashes just patchy redness ,the rash does not go anywhere else and I feel a bit itchy and anxious , this will last about 40 minutes then goes off totally .
Very worried as i can just be sat watching telly doing nothing and I am not a anxious person and never get stressed over anything .
Hope you can help
Regards
Neil