Answer: I'm sorry about your plant! I suspect that you inadvertently overwatered it during the winter resting period when it would also have appreciated cooler temperatures of about 50 degrees and little or no water at all.
In contrast, during the growth period, this plant prefers bright indirect light indoors and plenty of water and fertilizer.
You might wait and see what happens, but if it has rotted then it is probably dead. Here are some care instructions from the International Bulb Society, you might find them helpful next time.
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