Do you want to know the force or the pressure at the tip? Will this be changing rapidly?

Let’s assume you want the force first and you will calculate the pressure from the force and area. Is there any way you can infer the force by making a larger fixture and putting the strain gauge on that? You can also look at the material and infer the force due to gravity.
If you are in a lab you might be able to use a Rockwell hardness tester and work backwards from the result.
Is this a MEMs device? You can stimulate it with an acoustic signal and note the resonant frequency. Then work back from that using sqrt(k/m) .
If your lab has them you can play with the right size SAW device and work out the force from the assembly’s resonant freq.

Lots of possibilities. Not enough detail.