Help Needed With my Painted Kitchen Tiles Please!

[Sarah44]

I have just painted my kitchen wall tiles but managed to mess up one wall. I did it all properly , sanded the tiles then primed them and painted them with red tile paint then put in white grout lines with a grout pen . I'm really happy with three of the walls look lovely and shiny like new tiles but on the first wall I did I was too heavy handed with the grout pen and managed to get white grout on the tiles which wouldn't come off so decided to paint over them but could see brush marks and it looked uneven so I decided to sand all the gloss down and make it a bit more even and repainted with a roller , thing is now it has dried it feels and looks rough and is nowhere near as glossy and smooth as my other walls. Should I paint over it with a clear varnish , sorry for the long post , I'm a bit of a perfectionist so I can't just leave it like it is