Welcome and thanks for posting your query to HCM.
It appears to be from your query that you may be suffering from toxicity to some food additive or some chemical in the food. All the symptoms which you mentioned are systemic as well related to skin. But more pronounced of the symptoms are the systemic one such as metallic taste
. It is better to consult a physician at the earliest who can take detailed history and rule out the cause accordingly.
Meanwhile for the itchy patch you can apply fluticasone
cream and rake antihistamine tablet.
Hope it helps you.
With good health wishes.
Dr. Sanjay Kumar Kanodia