Could wet-sanding (ie w/sandpaper) 2 weeks ago be why i (still) have splinter hemmorhages + reddened/shiny/spongy nail bases? nails are purplish at base + tip, white in middle, fingertips seem puffy 2

Infection?: It's possible that the sand may have caused an abrasion leading to an infection especially if you did not wear gloves. I would strongly suggest that you see your primary care physician asap.

Infection?: What you're describing sounds like a bacterial infection. Staph infections are fairly common in people who have their hands in water a lot or use artificial nails. You should see a doctor to get an accurate diagnosis and treatment.