HELP - Wood undercoat on concrete walls - Newbie

[SMM]

I've made a mistake and applied wood/metal undercoat on concrete walls in a small'ish room. The aim was to try and cover up old red paint before applying a light blue matt paint.

It seems to have a gloss finish and I'm not sure if matt paint will adhere (its still drying so I haven't tested yet). Is it possible to paint over the top of it with matt? I would also like to try and seal the amount of gases it will produce as it has high VOC content and the room will eventually be for my 6 month yr old. Will applying two coats of matt paint seal in gases?

I was thinking of just sanding this down but it would be a reasonable amount of work to cover everywhere. Maybe there is another primer I can put on top of it to prep for the matt finish?

and yes I was high as a kite putting it on

 

[flameport]

Not likely to be a problem, and it should be matt when dry. It's designed to have other paint applied over it.

There are no 'gases' to seal in - that is just the solvents evaporating while it dries.