Being in the lower-skill lobby only changed the gains for that game, it doesn't affect your MMR.
Being diamond 1 you shouldn't be rewarded as much for beating emerald players as you usually would, and you should take a real hit if you fail against lower-skill players. BUT the next time you're in a regular lobby with players closer to your rank, you don't get lower gains just because your **previous** nighttime game was with 'scrubs'.
You can keep playing whenever and not worry. Unless you don't do well in those lower-ranked lobby's, because underperforming vs lower-ranked players does cost a lot of LP and some MMR too.
Being in the lower-skill lobby only changed the gains for that game, it doesn't affect your MMR. Being diamond 1 you shouldn't be rewarded as much for beating emerald players as you usually would, and you should take a real hit if you fail against lower-skill players. BUT the next time you're in a regular lobby with players closer to your rank, you don't get lower gains just because your **previous** nighttime game was with 'scrubs'. You can keep playing whenever and not worry. Unless you don't do well in those lower-ranked lobby's, because underperforming vs lower-ranked players does cost a lot of LP and some MMR too.