It’s not just a feed; your blog is ActivityPub compatible. The protocol supports editing and deleting content as well. I don’t know if @manton has implemented that for Micro.blog, though.
Yes, if someone comments, it will show up under your mentions in Micro.blog. And you can, in turn, reply to that comment from Micro.blog. In the same way, you can follow other ActivityPub compatible sources, like a Mastodon account, from Micro.blog. Just search for the full username:
Here’s an example search for @Gargron@mastodon.social.
But your blog is not a Mastodon account. It’s just a regular blog that speaks the same protocol as Mastodon, so some interactions between the two platforms are possible.
Micro.blog does not have anything like direct messages, so these messages should be delivered to you via email instead, according to the FAQ section in the documentation.