N95 mask

The most obvious reason is that the n95 is way too tight. If possible, try going up one size (I duno if there is a "large" n95, we only have small and regular at my place. Another trick is to loosen the stretchy straps by pulling on them a little harder/stretch out the strap before putting it on your face. Of course you don't want to loosen/stretch them out too much that the mask won't get a good suction. If your place has the supplies, the duckbill N95 would definitely lessen the soreness/tightness when compared to regular N95's.

If all else fails, you'd need to wear the astronaut set-up. Or, find another position. Also, depending on where you work, you may not need anything more than a regular surgical mask or any other medical mask that is designated as a "droplet" protection mask.

Welcome to my world.

At my hospital, we have to wear our N95s with a surgical mask over it for 12 hours. Many of us have a nose, lip, cheek, or chin issue with the mask. Not to mention dry mouth and acne from the heat and humidity. Many of us use a dressing of some sort; some like a hydrocolloid, some use a simple band aid. I use a Bandaid brand second skin over my nose. I wear it three days in a row (I know it sounds gross!), washing my face with it on, and remove it on my third and last shift. I use a good cleansing face mask to deep clean my pores after my three shifts. Get yourself some good quality skin care products. 

Some people have gone online and found their own masks rather than the ones supplied by the hospital. One that is popular with my coworkers is made with a soft gel edging that has replaceable filters. I didn't like the straps on that one, but everyone has a different preference, so try one and see what works best for you. Check amazon and cov.care.