Spots on Masdevallia Leaves?

[mnh3281]

Hi all! I am new here to post, although I have read on this site for quite some time and find it to be so helpful, so thank you all! I do have something to ask though - I have a Masd. Veitchiana which was doing fine for a while but I noticed some dark spots on the under side of the leaves that seem to be "puckered" if you will. The spots will eventually cause the leaf to yellow and die, and I am noticing it on some of the younger leaves. I love this orchid and hope to prevent it from dying, so any help would be greatly appreciated. I have looked for mites and scale and see nothing, so I'm at a loss. Thanks so much!