I knew that it would again have to come inside for winter, but this time it was staying at my house.... and I have two cats who will eat all plants, real or fake. I also noticed that the plant had little yellow aphids living on it. So I took a trip to Home Depot and picked up some pet friendly pesticide and sprayed the plant about 3 times. It was outside until it got down to about 50 degrees F.
When I brought it in, I put it in the sunniest room I could. However, it soon lost almost all leaves and began to look dead, not sure if the pesticide had anything to do with it. I bought it a grow light to help provide more light since it no longer gets direct sun. We keep the house around 73 degrees F. It still didn't seem to perk up. I have read many accounts of people cutting their mandevilla back for winter and letting it go dormant. I figured mine probably did go dormant.
Just yesterday I looked closely at it and saw a few new baby leaves!!! I'm just glad to know its still alive and well. I did not want to have to wait until spring to find out if I killed it. I'll add some pictures of how it looks, without all its leaves... its pitiful and sad looking.