I had a minor case like this earlier this summer. Picked up some stogies from an non-usual place, noticed a day later my Tat SW next to the "foreigner" in my humi had a "pin" hole. Immediately took out all my stogies and inspected them all for holes. Further, take your stogies and hold them above a white piece of paper with the foot pointed down, then give them a little tap like you're knocking off ash. If a good amount of black dust falls out, even if there's no holes visible, that's a sign of a beetle. The black dust is actually their feces. I then separate all my stogies by degrees of infestation. Any cigars with holes were immediately incinerated in a little bon-fire. Then I separated the ones with "evidence of fecal matter" into two bags; sticks with fecal matter, and sticks with only trace signs of it. All other sticks with no signs of holes, black dust (beetle $#*t) or any beetle contact were then bagged a 5er at a time and then bagged together in a bigger bag and placed in the fridge with the "black dust" bags separately too. 24hrs in the fridge, 48-72hrs in the freezer, another 36hrs in the fridge, then I set them out on my wine rack in my cellar (65F@62%RH) in the bags still with small Boveda Humi-packs in each smaller bag for a week. During this time, take your humidor outside and blow it out with compressed air, then go back inside, vacuum it out, wipe the insides down with a rag like you're seasoning it lightly again to collect any remaining "dust" or eggs left in the humidor. I then took a clean rag and repeated the process again, then set my humidor on my wine rack in the cellar as well until the sticks were ready again.
Even then, all stogies with any signs of fecal matter (black dust) were never returned to my Diamond Crown humi. Only sticks with zero signs of beetle contact were returned to the humidor. All sticks with signs of beetle contact were kept separate, in bags with humi-packs and inspected before any smoking. I ended up throwing out a handful of the moderate signs of fecal matter, the Tat SW with the hole and the three "foreign" sticks. A total loss of less than 10 stogies, and only about 5-6 have experienced any wrapper issues as a result of the deep freeze. I actually additionally let all clean sticks sit in the humidor for another week or so while I went through the "black dust" cigars. Not bad smokes still, didn't taste like $#*t at all.
Haven't had a problem ever before or since, and all things considered, I feel like I got lucky. The loss could have been far greater. Now, any sticks that aren't from my B&M never see my humidor. Foreigners get stuck in bags with humi-packs, just to be safe.