In most cats, seeing a protruding tongue, particularly if there are no other symptoms, is not a concern and can be extremely endearing. If, however, it is a new trait, is happening continually or your cat has other signs of illness, it is essential that you see your veterinarian for a checkup.
If your cat is struggling to breathe, eat or drink, or has any other signs of trauma, then seeking veterinary advice is an absolute priority. After all, it is better to see your vet and get the all-clear than to miss something that could be life-changing.