Repairing an artex ceiling

First you must let it dry and then clan the area , apply a unibond sealant to stop the suction, using artex your mix depend the pattern design , You have stipple ,slap brush ,bristle brush all need a smooth creme mix with stipple a little creamer

if your ceiling is plasterboard [depending on how much water affected it] when it drys it could become brittle so you may need to replace a section of plasterboard. if you have a pad pattern as opposed to comb usually can blend pattern in, but if a comb pattern more of a challenge...