(Reading "The Coming Plague" while in high school was definitely formative, for better for worse.)
A few years ago I lost some skin on an elbow just by resting it (i.e., rubbing it repeatedly)on a table too much while I worked at my computer. My skin was dry and I wasn't wearing long sleeves, which probably exacerbated the problem. I don't think my dermis was ever punctured, but I lost a bit of epidermis.
I ended up with an infection working its way up my arm, and it required level-two antibiotics to stop it.
This all happened just with normal indoor living. It's not like I waded through untreated sewage.
I'm a lot more careful now. 99% of the time applying a topical antibiotic and a bandaid is overkill. But the 1% make it a worthwhile policy.
Edit: could have been worse, but still very gross. Not Trypophobia triggering