One thing that I have found does smooth out that bite. Sometimes quite a bit is Oak. I did a test between non-oaked and oaked doing exactly the same with both and the oaked won hands down. Sounds like this is still in the carboy. Just take 1 oz of lightly toasted oak, or medium toast is good too and put it in a hops bag and drop it in. Possibly a couple of marbles to send it to the bottom as the oak will float. Then leave in for about a month. When you take it out, let it age another 2 months before bottling and drinking. New mead typically has that harsh back bite but it does age out and Oak helps it age a bit quicker and smoother.
I use Oak chips but oak cubes (sometimes called beans), or staves are ok too. I use american oak but there are other options: French oak and Hungarian oak. I am also experimenting with bamboo leaves.
Hope this works out for you.
Matrix