My plant was doing well but suddenly took a turn for the worse. Leaves almost look like chunks are in them.
Certified GKH Gardening Expert
This is likely Brown Scale.
As the insects grow they become fatter and may appear to be bumps in the leaves.
You can use a Q tip dipped in rubbing alcohol and wipe each insect away.
Spraying the plant with a insecticidal soap will also be effective.
Here are some links to help you.