Congratulations!!
I'm sorry but I don't have any experience with this either. All I can think of is using an "as featured in..." image wherever you can. In all of your social media, on Etsy if possible, at any markets you do, etc. Perhaps even a lovely little note to go out with any sales alerting your customers an item like theirs was featured in the magazine (while the magazine is in circulation that is, so they can keep an eye out for it if they like). Some customers would quite like this - proof that they have good taste!
If they are approachable I would ask the magazine how you can cross promote as well. Eg. They may be able to send you an image from the magazine (with their copy, layout & font, etc) for you to use for this "as featured in" purpose. I have often seen people at markets with this kind of sign that looked like it was a layout from the magazine. Presumably the mag has their own social media you can link to as well?
I don't have any idea how this works so this might be naive of me - but thought I'd just send you some thoughts of where I would start.
And yes as Cathy has said - totally ok to blow your own horn!! It's a fantastic affirmation of your art, and a wonderful opportunity to get your work out there! Well done and good luck!!x