I wouldn't have been accommodating. Connecting any foreign USB device can pose a security risk. The printer - I assume - is on the company network. So it would have been reasonable to reject his idea on the basis of security policy/compliance (If you are the IT there, no one should be able to argue about this)

As far as the making of such a mistake goes. Others have already suggested possible ways you could fix the problem, and as long as you try everything you can to remedy your mistake, you shouldn't feel too bad about it. You should remember the mistake and learn from it. Read system messages, and pay more attention in the future.

Every one in IT makes at least one severe mistake, that they need to learn from. About 6 years ago, I was sent to a customer to change the battery in a UPS. My boss showed me the procedure before I left - since I had never done any work on UPS's up until then - and he was like "open the cover, pull the battery out, push the new one in, and close the door. The thing will still provide power, while you do this."
When I arrived, I was directed to the UPS, it was sitting on the floor, on the carpet, behind the leg of a table. My thinking was, OK, just move the damn thing to the side. So I picked it up - since it wouldn't slide on the thick carpet - and the moment I did that, the power went out. I noticed a flap on the bottom, that cuts power, if the device is lifted from the floor. There was no redundancy in the power supply, and everything was connected to that UPS. So the server, where 15 engineers were working on lost power suddenly. My 5 minute job turned into a 1,5 hours of recovery. The customer lost precious time and work, and I felt bad for weeks.

Having learned from that, I had since then saved several customers from similar situations. I have had some negligent and reckless colleagues over the years, and even experienced ones often assume the power supply is always redundant, and nothing can happen.

I know someone who accidentally destroyed the SQL database of the ERP-System of a company, because he confused the prod and the test systems, and made a mistake in a query. He replaced every single data point with the number 666. There were backups, but the downtime and the loss was still massive.

Another caused a government institution to be hacked, by setting and leaving the root password of the ESXi Server as "root", and the machine exposed to the internet. An entire county was unable to provide their services to their citizens fro months as a result.

Bottom line. Don't feel too bad, everyone makes mistakes, and as long as you recognize that you have, and do what you can to remedy it, you are a good person. And even if you feel the imposter syndrome (like we all do from time to time), it is absolutely normal. Try taking things a bit slower for a while, and pay more attention, till you regain your confidence. And talk to a friend about it, that definitely helps you deal with it.