The mystery of what is ailing rocker Avril Lavigne is over. She has Lyme disease.
She thinks she contracted the disease last year, when she was apparently bitten by an infected deer tick in her native Canada.
ABC News Chief Health and Medical Editor Dr. Richard Besser told INSIDE EDITION, "The tell tale sign of Lyme disease is a rash. It is called a 'bulls eye rash.' If you develop that rash you need to see your doctor right away."
The disease really knocked her out of commission.
It also left her fans puzzled over her sudden disappearance from the music scene. They left messages like these on her web site like “Is Avril ok?” and “Where did Avril go?”
The 30-year-old was so sick she even had to have her mom move in to take care of her.
Dr. Besser said, "There are people that have symptoms for months and others that have symptoms for years."
She says she's not fully recovered but is about 80% better.