Scale on this denphal or something else

[estación seca]

I'm not sure what you are asking about. The round black spots on the leaves are probably bacterial or fungal. Are they enlarging?

What is the light brown streak on the underside of the leftmost leaf? I can't see it that well.

How long have you had it?

Are you growing it indoors, or outdoors? What are the temperatures and humidity in the growing area?