The article on migrating Minecraft accounts to Mojang accounts has a link to change skins:

Ability to change your Minecraft skin and cape at Minecraft.net

That link goes to https://minecraft.net/login/?return_url=https%3A%2F%2Fminecraft.net%2Fsv%2Fprofile%2F%3Fref%3Dbm%23%2Flogin%3F_k%3D5jznpy, which redirects on log-in to https://minecraft.net/sv/profile/?ref=bm#/login?_k=5jznpy. The problem is that that URL is the sv version of the page - i.e. Swedish, while the article itself is in English. While most of the page is still in English, some things (particularly the menu) are not.

The corrected link is https://minecraft.net/login/?return_url=https%3A%2F%2Fminecraft.net%2Fen%2Fprofile%2F%3Fref%3Dbm%23%2Flogin%3F_k%3D5jznpy (en) or perhaps https://minecraft.net/login/?return_url=https%3A%2F%2Fminecraft.net%2Fen-us%2Fprofile%2F%3Fref%3Dbm%23%2Flogin%3F_k%3D5jznpy (en-us).