I'm in the exact same position right now! I overpicked a big zit which was under the skin on Wednesday and its currently a scab.. some of it has flaked off a little but I'm trying SO hard to distract myself from picking it/looking at it so it can heal!
I used to get myself into these situations A LOT (I'm a slowly recovering obsessive picker!) so I know how to deal with them quite well. Here's what I find really helps:
1. After gently washing the scab in the evening, lightly pat dry with towel.
2. Apply some tea tree oil or apple cider vinegar (both work really well) to a cotton ball and gently dab onto the scab for a few minutes. Both of these products have antiseptic qualities which will keep the scab clean and prevent infection
3. Let it air dry, and then apply a layer of a good, natural aloe vera gel. The one I have is 99% aloe and it forms a clear barrier over the scab when it dries and helps it to heal so quickly while keeping it hydrated to avoid painful cracking. Aloe vera is amazing for healing!
4. After the aloe has dried completely, apply a thin layer of antiseptic healing cream (something like Sudocrem or Savlon) over the scab and cover with a plaster/band aid. This keeps the products on the scab and helps resist the urge to pick/stare at it. Plus, Sudocrem is amazing at reducing redness and pigmentation. I continue to apply it even after the scab has gone as it fades pink/red marks really quick

If you do this every night you will notice quick improvements!