Demi Lovato Cancels Rest of Tour in Wake of Rehab

It's becoming more clear now that Demi Lovato will be in treatment for a lengthy period of time ... canceling the remaining shows on her tour.

Demi's Tell Me You Love Me tour dates in Mexico and South America have been scrapped. The news comes on the heels of Demi leaving Cedars-Sinai Medical Center in L.A. just days ago and jetting outside of California to a rehab facility.

The singer was scheduled to perform September 20 and 22 in Mexico but those dates have been canceled. Also canceled is her 6-city tour in Chile, Argentina and Brazil slated for November.

Live Nation and Lotus Productions "wish Demi Lovato the best now and in the future and we hope to see her soon in South America." Refunds will be made available beginning Friday.

TMZ broke the story ... Demi's entered rehab at one of the nation's leading facilities for addiction.