Hi Quinn. IMHO it might be a combination of problems, not just one. The pests highighted in the red circles look like scale insects to me. They always gather around the midrib of the leaf on the bottom surface. Secondly, the silvery undersides of the leaves with desiccated texture (most evident in last pic) show symptoms of spider mite attack. I would spray the entire plant with neem oil/white oil. Instructions can be found by googling.
