Thank you for your patience. There are quite a few possible causes for Ozzy's symptoms today and we need to consider anything from him falling and hurting his throat, to a toxicity, or even a primary cardiorespiratory issue. Hopefully Ozzy is up to date with flea, worm and heartworm treatments. You are definitely going to need to continue to keep a close eye on your boy for the next few hours if you can, and for now - definitely encourage him to have a good drink of water in case there is something lodged in his throat. If he seems to be very restless, or has any issues breathing right now, then please do what you can to get him seen straight away.
For now, please keep a close eye on Ozzy's mucus membranes, capillary refill time and respiratory rate as follows:
Mucus membranes - flip his lip and look at the color of his gums. They should maintain a nice salmon pink color. Get him to the emergency Vet if they appear white or very pale pink, or if they are a dark deep red color.
Capillary Refill time - this measures blood perfusion and test this by putting your thumb on his gum to apply pressure. After you release your thumb you will see the gum blanch. Capillary refill time is the amount of time it takes (in seconds) for the gum to return to a healthy pink color from the blanched white color. If 2 seconds or less don't worry - if it is taking significantly more time, again - off to the emergency Vet.
Respiratory Rate - if he is continuously panting throughout the night, this is a sign of shock and or pain and a signal for a trip to the emergency Vet.
All the best with your boy, and as above, because there are quite a range of possible causes for Ozzy's symptoms, if the coughing continues, definitely play it safe and have him seen tonight. I hope all of the above makes sense? If you have more questions or if I can help in any other way, please do not hesitate to ask! If you would like to accept my answer, please press RATE OUR CONVERSATION (I am not compensated in any other way). Bonuses are always welcome. Thanks! I hope to work with you again soon!
PS: If you have additional questions after you rate the question, you are welcome to request me for additional conversations if I am on-line or by beginning your question "Dr. E..." or "Pet-doc..." and others will leave the questions for me.