If you find yourself in that hold, you're calling ATC for your next steps.
The holding pattern depicted on this chart is not for aircraft on the approach. Once you've completed the PT, or one of the arc entries, you should be proceeding straight-in at that point.
The dotted line indicates that the hold is, instead, for aircraft that have gone missed. This can be verified by reading the missed approach procedure where it tells you to climbing-turn to Drake, and then climb-in-hold at Drake. Compare to the hold depicted as part of the ILS/LOC 2 at KEEN, which is a solid line and so is part of the approach procedure (though it's pretty much only used for hold-in-lieu-of-PT unless KEEN is busy enough that ATC needs to stack folks up in that hold). At KEEN that hold is also part of the missed approach procedure, but it's not dashed, because it's not exclusively so.
The most likely event where you end up in that hold is that something went wrong on the approach and you've gone missed. You're outside KPRC's Class D and since you're IFR that means you're reporting the missed approach to Phoenix Approach so they can clear the next person in or out. You're not going back down to KPRC without a new approach clearance.
Flying the missed-approach hold without ATC instruction to do so is potentially dangerous as it would be unexpected behavior. The good news is, KPRC is Class D, so presumably if there's any confusion as to what you should be doing, Tower can provide clarification as to what's correct there; or if you're above 7,500, Phoenix Approach.
If it's after hours, CTAF is your friend, and entering a hold should definitely be something you let your fellow pilots know you're up to, anyway, since it creates the possibility of opposite-direction traffic.