Crazy teeth

So, Chloe has been teething these past couple of nights and I assumed that she was getting an upper incisor as that's the proper order of getting her teeth.

Now, I did my research and followed the above chart for putting the numbing medication on her gums. It's not like you can see anything coming in until the tooth bursts through the gums. Her bottom teeth have been visible  through the gums since she was four months old but she didn't get her first tooth until she was 10 months.
Anyway, so I'm putting the numbing medication on the upper gums on either side of her central incisor. Well . . . Mommy did wrong.
I dug out my head light Friday morning to fish around in her mouth.She'd kept us up the night before so I wanted to see what was going on. So, I'm poking around in her mouth and I can't see anything. But out of the corner of my eye . . . I see this flash of white on the right upper gums -- way in the back. I was absolutely horrified. HORRIFIED.
The white was the full surface of a molar that had come through the gums probably about two weeks ago. I felt around on the other side of the mouth and low and behold found a sharp edge of a more recently erupted molar. EEK.
She was teething around her birthday two weeks ago but I didn't see anything come through so I figured it was one of those preliminary teething episodes when the tooth moves through the canal but isn't ready to come through the gums. How wrong I was.
I felt terrible all day that this tooth had come through and I didn't even know it to sooth her pain.
The worst part is that's not the first time that's happened and I guessing it won't be the last.