Flaking paint

[Sue6655]

Hi,
I’m sorry if this has been asked before.
I had a leak thru the lounge ceiling a few weeks ago, that has now been fixed.
Obviously it had left stains on the ceiling , I scraped away all the flaking paint and have done the Zinsser peel stop and then stain stop. I believe I need to fill the edges with filler ? But when I sand it down will I not sand off the zinsser and stain stop?
I hope this makes sense

 

[Wayners]

You fill and sand smooth first. Then stain block. Products like Zinsser BIN will seal the filler and stain block...
if you use peel stop first. Fill. Sand filler only with 180 grade. Paint. If it stains then use a stain block. Paint.

With stain blocks you sometimes use first and sometimes you use last thing before you paint