Good Morning and welcome! I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
This may or may not be related. The cough could be due to allergies and the blistered penis could also be caused by this. The treatment for this is Benadryl available at the chemist over the counter at 0.5 mg per pound every 12 hrs orally and then apply a cortisone ointment to the raw areas of his penis every 8 hrs if Leo will let you. I would also recommend that you start Leo on a course of antibiotics since these blisters on his penis may be partly a staph infection from the irritation. You will have to get this from your vet. If there is no improvement within a day, have your vet check Leo to be sure we have not missed something.
The cough also may be an upper respiratory infection which may require antibiotics to get Leo last this.
Does that make sense to you?
Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please REPLY so I can clarify for you.
Sincerely, Dr. Loretta