With the best will in the world, we can't always check everything.. sometimes we're too exhausted after a tough day, or there's too much of everyone's stuff everywhere to check properly without disturbing others. And no guarantee with private rooms, but probably less likely than in a dorm.
I was severely bitten on the Norte once, I woke up covered in bites. The hospitalero of the private albergue wasn't interested. I stopped in a china shop in the next town and bought a cheap t-shirt and shorts, found a private room, put them on and brought everything, pack and all, to a laundry and threw everything in the dryer. Ruined my crocs, they shrunk two sizes, never to fit me again. At the medical centre I got a cortisone shot and a prescription for cream and anti histamines. It took a few days for the swelling and itching to subside, but what I really remember was the feeling of shame, that I had done something wrong.. quite irrational, really. Since then, and that was six years ago, I've been more careful, and perhaps lucky too.
Sounds like you're over the worst of it, glad it didnt spoil your camino..
