Hi, I am sorry to hear you have concerns about your boy. I had a similar issue with my
piggie Susie however, it was when she was around 6 months old symptoms began.
Like your boy, she kept developing crusty nostrils and her nose was also clear/sometimes green fluid/crusts. She also had laboured breathing now and again.
I was to and from the vets like a yoyo, my Susie had more than her fair share of antibiotics and unfortunately went into stasis however she did survive this. It wasnt until we saw a specialist that we got to the bottom of her illness.
It turned out she suffered from what the vet compared to as a human deviated septum and told us the condition could be managed however unfortunately, not cured. The vet advised us to get a nebuliser and supplied us with something called f10 antiseptic solution, that we had to dilute down with water. We put her on nebuliser everyday, working our way up gradually from 5 mins a session, to eventually 25 mins a session. Over the space of around 10 weeks. The treatment did work and her nose/symptoms were around 90% improved. We did this till she unfortunately passed away.
Unfortunately, my Susie passed away from surgery not from her breathing issues. I would definitely book a vets visit as a hands on examination is crucial if it may be the start of a URI. In my opinion, you really need to investigate the issue and rule out possible health issues. It took us months before we were given a diagnosis and your boys issues could be completely different however, it does sound similar. I hope he is OK and you get to the bottom of this. I wish you and your boy all the best.