Three dead power outlets, no tripped breakers
We are talking about garage and outdoor receptacles. These are both required to be GFCI protected. It is extremely easy to trip a GFI if you are working on the circuit live. Simply touching the neutral to ground, or even testing from hot to ground can trip them.

You have a tripped GFI somewhere, you need to find it. Could be nearly anywhere; garage, somewhere outside, near the main electrical panel, etc.
Let us know what you find.