My puppy's voice is deeper and he lost it. Is this a health problem?

This could be normal or it could be sign of an infection. If he is coughing, sneezing, lethargic or decreased appetite then I would consider taking him to the vet. Any of these signs could be additional clues that he could have an upper respiratory infection. If Max is a big barker and has recently been barking a lot then he potentially could have just lost his voice that we do sometimes. Over a few days, it should return to normal if that's the case. You can try 25mg (one adult tablet) of Benadryl twice a day in case it is allergy related. I have seen some dogs just have a small change in the voice as they get older but it usually a gradual change. If his voice isn't improving, worsens or he starts to have any of the above symptoms then I would have your vet take a look at him. your vet will be able to do an exam and listen to his heart/lungs to ensure everything is clear. Your vet will also be able to do blood work and X-rays if needed and provide the proper meds. I hope this helps!