Creating clothes in sculpt mode with mask leaves jagged edges

I’m trying to create a business suit for this bear using the lasso mask tool in sculpt mode… here is what I’m talking about

see I’m making a mask in the shape of a business suit but there’s jagged edges along the edges… it’s not smooth and I would like to make it smooth… can you help me with that. I added the subdivision surface modifier but it doesn’t seem to help. It’s supposed to look like this.

This is from a tutorial I’m taking. Here’s my blender file. any help on this would be awesome!(note I also tried multiresolution modifier up to a subdivision of two because my computer was kind of hanging when I did two but that didn’t seem to help either)

(NOTE: I figured it out all you gotta do is hit A and then smooth mask)