Hi.. Thanks for the query.. Metallic taste in mouth along with sores and red patches can be due to causes like fungal infection or oral thrush, acid reflux, allergic reaction, throat infection, side effects of medications etc.. So first of all you should get a clinical examination done along with oral swab culture for ruling out infection.. Treatment can be done accordingly.. As of now you can gargle with specialised mouthwash like Magic Mouthwash.. You can chew sugar free flavoured chewing gum.. You can suck ice pops or rinse with cold water to reduce inflammation.. Avoid spicy and irritant foods as they can increase inflammation and pain.. You can also take Vitamin B complex supplements.. Hope this information helps.. Regards..