In the US, even with a referral, dermatology is not considered preventative, so high deductible POS plans are left to HSAs too.

My HMO pays almost 100% of in-network care with a referral (there is a nominal per-visit co-pay), so that at least wouldn't be an issue there, as long as I don't run into silly things like "The facility you visited was in-network, but Person X who did some of your care was an out-of-network contractor" which has bit me for emergency care before.

It might be a worthwhile investment in self-preservation.

Sounds like your GP isn't doing their job? Time to get a different one.

Fire your GP.

I'll try, but my 3 previous GPs, who were all better than my current one, are no longer in-network. Presumably the insurance doesn't pay well enough to keep the better doctors. It's a substantial amount of paperwork (both with the insurance and the new GP) with no guarantee things will be better.

They probably can't depending on insurance.

Insurance isn't a suicide pact that ties you to one particular, shitty GP.

For many people it is. They cannot see another doctor if they want to continue doing things like eating food. If they're lucky enough to be insured at all.

Could you explain the mechanism of this? I am unsure how this situation could arise. There are seemingly infinite GPs in-network on any insurances.

Is their GP the only practitioner in-network for them? Their network has one member?

No, but changing your GP normally requires a new patient consult.

Many GPs aren't taking new patients (or at least from whatever insurance you have) or the initial new patient visit may take 4+ months to schedule.

GP is not a particularly popular choice for doctors as it pays significant less than any specialty does.

Depends if there are other in-network GPs in a range where OP can reasonably travel to.

And who are also accepting new patients.