Damian's Quest

Is there more things to do after helping Damian in the deep cavern because after I help Damian I did not see him in the dream realm where I can receive his starter and shaymin

You have to complete the elite four rematches to get them, but be sure you have enough space in your party for them both, because there is a glitch where if you have a full party, he might not give you his starter

ok thank you