It's not so much about how much exposure you have, it's about what you're doing on your page, because what they really need access to is your audience.
So if a page were focused on skin care, for example, they know that audience is interested in skin care, and that's really what they're paying for with PR packages - exposing their brand and product to 40,000 people who are already interested in what they do.
It might be tough for you to find a company willing to sponsor or send things if there's nothing on your page specifically relevant to a product or service that they offer. If you do dance or anything like that along with it, you could try reaching out to sponsors like Steezy (at home dance classes).
You could also take a risk and start sprinkling a couple videos focused on the type of PR you want into your regular content and once you have established a base of it, reach out for PR stuff then - the only risk is that people who follow you for your lipsyncs may not be there for that kind of content and you may lose followers in the meantime.