Hi.. Thanks for the query.. Burning sensation inside mouth with a peppery /and metallic taste can be due to Burning mouth syndrome.. Burning tongue/mouth syndrome is a condition in which there is burning sensation inside mouth and can also be associated with a scalded feeling and can also experience numbing sensation.. It can occur due to a number of causes like nutritional deficiency of iron and vitamin B12, dry mouth or xerostomia, stress, acid reflux, side effects of medicines etc.. I would suggest you to consult an Oral Physician and get evaluated and a thorough clinical examination and investigations like blood tests can be advised.. Treatment of underlying cause will resolve the symptoms.. As of now to get relieved you can start gargling with a numbing mouthwash containing Lignocaine.. Take anti inflammatory painkiller like Ibuprofen.. Avoid spicy foods and take a soft bland diet.. Suck ice pops.. For dizziness and tiredness you should first get Vitamin B 12 levels and blood pressure checked. Further investigations and management can be done accordingly.. Hope this helps.. Regards..