If you see little holes in the leaves and some lines check for raised dirt around the plant. Moth larvae like to live in the soil near the plants base. They will come out of the soil at night and chomp stem and leaf material. If your seeing holes and lines inside your stem you may want to look into Eurasian hemp borer and those are bad. As for the black spots look on the underside of the leaf and see if there's mites or other little buggies. Just don't freak out. The part that kills most plants is the panic moment of I need to fix this.
Same plant as other thread? If so I don't think you have anything to worry about. Just keep posting pics and I and others will try and help with info when you need it
