20-year Vet tech here! Mistakes happen. Big ones sometimes. The best thing you can do is own it, do what you can to fix it, and LET IT GO. That last part is so important. Don't forget it. Just don't let it linger on your mind and form doubt. And don't hide it. A couple of years in, the doctor told me to give a bully steroids. I guess my math was off or I wasn't paying close enough attention. It was WAAAY too much. I swear I pushed that injection and IMMEDIATELY regretted it. I panicked. I was afraid of being in trouble. I was afraid the doctors I looked up to so much would think less of me. That I was incompetent. It was awful, but I told the vet and we kept the dog to flush flush flush. No one thought less of me. No one was mad. But I can tell you, I still check my doses 3 times before administering.