My Boss and the Coffee Stain

I work in retail at this big-box store, where my shift starts early. The morning rush is always hectic. My boss, Alex, likes to come around mid-morning for a quick check-in before leaving me alone again. It was just another Monday when I had an emergency bathroom break and rushed back with the coffee station as my last stop. That's when it happened: a big spill of black liquid all over the white countertop. I panicked, thinking about what Alex would think seeing such messiness from his favorite employee (he thinks highly of me for some reason). I grabbed napkins and started cleaning quickly, trying to mask the smell. By the time Alex arrived, most of it was covered up. He said he needed coffee but didn't offer to help clean or notice anything out of place. After a few minutes, though, the stain reappeared under the paper towels as the liquid soaked through. My heart dropped thinking about how unprofessional this looked. I quickly cleaned again and put out fresh grounds for him. He left satisfied with his brew, totally unaware he’d missed the mess. I've been overthinking this since, am I being overly critical of myself? Maybe it's okay to let some things slide sometimes, but part of me can't shake the feeling that I was caught doing something subpar and could’ve handled it better. Maybe I'm just too hard on myself at work.