Tamoxifen and toe nails.

I have been on Tamoxifen since April 2016 and my toe nails since chemo have always been a little odd. Often growing in a raised ^ rather than a nice curve. Lately both my big toenails are receding in the nail beds and I have lost half of the nail attachment in a matter of a few days. If it continues I will end up losing both nails. It is not painful although I do still have a bit of peripheral nephropathy on some toes. Could it be my body has had enough of Tamoxifen? Walking bare foot on the beach in the sun while on Tamoxifen wouldn't be killing the nail beds would it? I had it during chemo but not since then, until now.