go to the local hard ware store and get some plaster patch its a compund that you mix.It has a bonding agent in it the adhear to you existing plaster and streangthen the wall. I patched some walls like the in my 1923 home. i was not using a textured wall but after the plaster patch dryed i applied all purpose dry wall compund to flush up the wall surface. sanded it flat and feathered the edges. now it looks as good as new.