What Causes Darkening And Itching Of Lips?

hi im an a 31 yr old female in new orleans louisiana. i am currently haveing a problem with my lips. for the past two weeks i have noticed they are getting darker and are itching and burning. i woke up one morning and they were burning really bad and everytime i woule wipe my mouth it seem like pus or something was leaking from them. i have been using blistex and that sort of helps from itching but it only helps for a little while. anything else i use on my lips really burn. i havent eaten ang out of the ordinary, my diet is the same as its always been. i stopped using the lipgloss i used to use for 4 days now but my lips are still bothering me. i think it started when i awoke one night and took a sip out of a water bottle i had by my bed and after i drunk from it i smelled a sort of metallic smell but i didny think much of it but when i woke up the next day thats when my lips started burning. i am a type 2 diabetic also.