Breathy voice for 6 weeks

Hi there. I`m really anxious about my voice. It sounds really breathy and all i can describe it as is quite rod stewart like. It`s been around 6 weeks now and though i am not getting any worse my voice isnt getting any better.I have sung regularly in bands for the last 10 years and havnt had anything like this. I also have a tickly dry cough. My GP has assured me i have some sort of allergy but im worried ive done some perminant damage to my voice. Back in january i sang with a pretty bad cold and fear my trouble evolved from this. I don`t have any pain at all and though i normally have a high register im finding i can go even higher without really pushing it. If my vocal cords were damaged would i have pain and how long could i expect this thing to go on?? Any help would be appreciated.