I dress my punch and pritchel maybe once a week, with much use. 
Properly worked tools should not mushroom nor need dressing/fixing
Except for when the tool is forced beyond its work.
ie. the head stamp will only go so far through the shoe,
then it will mushroom if hit much more.
A prichel should not mushroom nor bend unless the pritchel hole is missed.
Fixing either with a hammer is not acceptable,
head stamps and pritchels are Precision Hot Tools
and need to be built as such and maintained as such.
I have post the following a couple of times in the past
but it never hurts to post again.
Heat Treating H13
First h13 is the best Tool Steel to use for hot work, and this is why, when you are working hot the tool heats up, and of all the tool steels, it will retain its hardened properties, to a higher temp. And will retain is properties at that heat for a longer period of time, than all other steels. When you buy h13, it is in its annealed (softened) state, so those who machine the steel are able to, off the rack.
These are the steps necessary to have nice working tools that you will only need to touch up once a week or so. (That’s one punch and one pritchel per week!!! Even making a lot of shoes.) First never work h13 as high a heat as yellow, or as low as a dull red, or less, as you will destroy the steel for the intended use. First raise the temp. of the steel slowly as this will ensure there is a core heat. Work h13 at a near yellow heat to a red heat. After you forge h13 to a punch or pritchel, you need to relieve the stress created by hammer forging. This is done by after cooling the worked h13, reheat slowly to near its critical temp, which is 1860’f. Then stuff it into a bucket of finely sifted coke ash and allow to cool slowly. Now it is ready for heat treating.
NOTE:
NEVER EVER QUENCH IN WATER OR OIL,
AS h13 IS AN AIR QUENCH STEEL ONLY.
Heat treating h13 is as such,
Again slowly raising the temp. to near critical, and holding for a time then raise the temp. to the upper critical temp. about 1870’f. ( near yellow )Hold at this temp for a time. Then quench the h13 with pressurized air. I use a portable air tank rigged with a regulated air flow so as 100lbs will release slowly over ten min. or so. I shoot the air at the tip of the punch so it flows around the tool and down the shaft until a black heat, and then let cool in a standing air ( still air )
I don’t temper the hardness, but for the odd time that you might beat the end of your punch into the anvil or use your pritchel on cold steel to open cold a nail hole you forgot to check, then you may wish to temper the hard ness by taking the hardened tool and raising the temp into dull red, and the leave in still air till cool to the touch, then repeat the step again.
The next step is hard for me to reveal as it maybe the edge needed in a competitive arena.
So for the working Farriers, I have a belt sander with a 6” disk, which I use to work the five surfaces of the punch and prichel, giving it a very smooth surface with razor sharp corners. This is now a cutting tool. One hit to set the punch into the shoe, the next to drive it, the third, a little softer to hear it hit the anvil. No more. (when the punch has gone as far as it can through the hot steel, there will be a distinctly different sound when you strike the punch).
When using the tool I quench in pine tar ( forshners ) every hole or every second hole. One, not to cool the tool, but to keep it from getting to hot, and two, the pine tar liquefies on the tool lubricating it.
No matter what you do to treat your tools or what type of tool steel you use, if you beat it into the anvil the end will mushroom. With this method, after I head set, and then pritchel, one or two hits with the pritchel, as I’m lifting the shoe with the pritchel, off the anvil many times it will just fall off of the pritchel. I really love it when that happens.
I hope this helps. Let me Know.
Exerted from an article on my web site