Loss of voice after flu.

Hi Charlie, I had a bad flu in January this year and although 80% better I still have some weekness and loss of voice in the middle of my range [I am a singer]Swedish bitters have been suggested, which I have not been able to find in the UK, and cayenne pepper which I can get, but don't know how to take. Would you be kind enough to help please. Incidentally I had a most peculiar uncalled for agressive response from 'you know who' on another forum. I put it down to PMS! Best Wishes, Deotima.