If it were me, I'd remove that flare and redo it. Since it's offset, when you put the flare nut over it, it will move off-center and it'll likely leak or give you problems down the road.

If you have a 1/2" fluted countersink drill bit, those are great for cleaning/prepping the end to be flared. It'll remove any inside material when you cut the line.

Edit: Some photos. The chamfered edge gives the flare tool a nice centered hole to go into. Keeps everything straight and tidy






My OCD goes haywire with brake lines because my cars carry my family. I don't take any chances.

 

AND blow them out with compressed air to remove the metal debris..
I like using NiCop can't go wrong

 

Deburring the line is critical. Even a touch with a file will work. Worn out tubing cutters make poor cuts.

 

File the ends flat and square. I used to use the flare clamp itself, clamp the line in not very tight and use it for a guide for the file

 

Remember If you bend your own lines, don't forget the flare nut.

 

"Reaming is fundamental"

 

Absolute must when doing brakes.....
But, in all seriousness, take no chances. Do it right. Or, in this case, redo it. As others have stated, a wore tubing cutter or flare tool. Sometimes it just happens with new parts, too. All good, you'll get it.

 

Somehow I've turned into an old guy and in that transition time, I've made a lot of double flares. With that, I've seen it all! The offset problem, uneven flares, lopsided ends that don't sit level in the flare nut... the list goes on. A couple of years ago I saw the Eastwood flare kit and thought... what the Hell! I pulled the trigger and spent the money. After receiving it and going through the usual learning curve, I have to say, it was worth every penny!! Beautiful flares every time!
Just my two cents....