That certainly looks better Gabe!
Not sure which of the pesky things that is, but read through this ATP article about handling pests that attack the semps:
The thread "Aphids and mealy bugs" in
Growing Pains
In the meantime, isolate that plant away from your other plants. Sometimes I start first with a solution of water and alcohol and spray it on the plant while it is in shade, then observe if the condition of the plant improves. I try to avoid the heavier stuff initially, oftentimes, it may also affect beneficial insects once it is applied.