Help My mouse is Sneezing constantly

Hey all I have a problem with Ozz one of my Male mice. He has been sneezing pretty much constantly when he's awake. He was sneezing a bit the last few weeks but this last few days it's been really bad I don't know what could be wrong. Was using pine bedding but recently found out he could be allergic to it to I removed that last night and gave him toilet paper and hampster bedding. The sneezing seems worse this morning. Ozz was caged with My other mouse Spike for a couple weeks before I realized they were both male They were seperated 1 week ago. Spike is fine. so eny suggestions on what the problem could be...