Weight paint deletes whatever is painted


I’m new here. I’m also pretty new to Blender. Recently I’ve created a character and now I’m learning how to rig it. I figured out how to assign vertices with weight paint and things have been going well, but now when I select a bone and go to weight paint the area, it deletes whatever it is painting. I’ve searched all over for a fix but couldn’t find anything. It’s driving me nuts. Any help would be appreciated. Attached is a picture of what is going on. The picture is the neck of my character after using weight paint.




Alright I figured it out. I guess I just didn’t understand how it worked exactly. Sorry for the dumb question. I’m not sure how to delete the post.