Parts of my object are reversed?


I’m sorry advance for the lack of terminology in this post as I am new with blender and sculpting in general. This hindered me from simply googling my problem since I don’t know what to look for. There’s a part in my model that seems to be selected or highlighted and whenever I sculpt on it, it does the opposite thing like when I add it subtracts.
I remember editing this part of the arm during the first stages of making my base mesh and I remove a edge because
it was overlapping with another. It also removed the faces of that part so I added new faces manually (select vertices+f).
I don’t know if this is the cause of the problem or if I accidentally pressed something that causes it.

I’ll add a screenshot of the problem in the attachments.

Thanks in advance, cheers!


Remove any faces inside your mesh
Remove any double vertices (select all vertices and W / remove doubles)
Recalculate normals (select all faces and Ctrl+N)