As described to me by a couple of professional musicians who have absolute pitch (I don't) it's not so much that you lose it as that it shifts. For example the

As described to me by a couple of professional musicians who have absolute pitch (I don't) it's not so much that you lose it as that it shifts. For example the qualia you experienced for a B might now be felt in response to a slightly flat C, the whole sensation having shifted by a bit less than a semitone. This sounds vastly worse than just "losing absolute pitch" and was an extremely unpleasant and life-changing experience for the people that described it to me. Hearing about it was enough to convince me that absolute pitch is more of a curse than a blessing for musicians.