Q.I have lumps on my Hibiscus branches where leaves should be.
I don’t know what to do about this problem. I also had a hibiscus tree that just up and died in the late part of winter. I had them both in a window where they got sun in the morning. Doing great all winter. Kept them watered. Before the plant I have now dies I hope to understand the problem.

Certified GKH Gardening Expert
Hibiscus do not winter well in most homes. Although it is a little late to prune, it will benefit from a pruning to help regenerate. They are also very heavy feeders, so repotting it in fresh soil, or adding some compost or other nutrients can help as well. Give it plenty of sun, but some afternoon shade until it recovers.
This article will help you to care for Hibiscus: https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/how-to-care-for-hibiscus-plants.htm