It does look like it needs another week at the very least. Are you AT 8 weeks or at the END of 8 weeks because that is also a big difference for most strains (Day 50 vs day 56). You will see massive swelling in the second to the last week before proper harvest time with very little new growth. The very last week before a plant is truly done you won't see any new growth aside from a few stray pistols protruding out of massively swollen calyx, it also isn't putting on weight anymore but converting THC in the trichromes to CBD.
I had a few plants that looked like this, I stressed them out really bad and the never really got "swull" if you know what I mean.
Anyhow, keep up the good work!