I don't know if there is a way on amethyst to tell if someone is following you on their profile but on my profile I can see all my followers. Click on your profile picture at the top, not the home button. The home button is more like the followed feed on Twitter.
Discussion
In my own homepage I can also view all my followers and followed people. For example, on Iris and Snort, when you go to someone's homepage, it will show at the top whether they are following you or not. Is this feature not available in Amethyst?