blotch blotch /ˈblɑːttʃ/

noun

1. () An irregularly shaped spot  ( splodge , splotch , blotch )
   an irregularly shaped spot
   

verb

1. Mark with spots or blotches of different color or shades of color as if stained  ( blotch , streak , mottle )
   mark with spots or blotches of different color or shades of color as if stained