No, you can’t use the B Corp logo on your products or in your marketing.
Selfnamed is a Certified B Corporation, but the certification only applies to Selfnamed as a company and doesn't extend to the brands we produce for. That's by design: every company and brand has to qualify for B Corp on its own merits.
If you wish, you're welcome to mention that your products are made by Selfnamed, a Certified B Corporation, and to link to our public listing if you'd like to point customers to the source.