Can't texture paint?

this is my first time texture painting, so i was mainly experimenting. i tried to see what the F mask does, which i didn’t really get what it does, but when i switch to any other tool now, nothing works. what did i do?

You just need to disable your stencil mask an you will be able to use the tools normally again.

how do i do that in 2.79?

huh? i didn’t withdraw the post, i need help o_O

Here:

i can’t tell if it worked because, for some reason, when i opened my blend, now the model is jet black as though it doesn’t have a texture. i’ve reloaded it before without any problems, so i’m not sure what’s happening.

can anyone help me with this issue?