Dogs penis has golf ball swelling towards the base, that goes down while peeing. When sheathed, dogs penis seems harder than usual (maybe haven't noticed before) Dog has also been horny lately, humping people when excited which is a new behavior. 4 years old male.

I noticed the swelling this morning, which promptly went down after he peed. The humping and hard sheathed penis I noticed the past week.

For the full summary which spans 2 months, maybe this could be a cause.

2 months ago, we were at a motel and they had stray cats with fleas. My dog takes a flea and tick chew, but I noticed a red dot on the very tip of his penis. A week later there was minor swelling at the tip.

It stayed the same for another 2 weeks (red dot went away), untill we got lice at a different motel, which made the swelling slightly increase, more pus than normal, and one moment of incontinence, which has never been an issue.

I took him to a vet 2-3 weeks later, 3 weeks from today, they could not get a pee sample from him, but treated him for a uti anyways, 10 days/ 2x a day.

That seemed to help, pus is back to normal, the swelling I think is a little better, and my dog stopped trying to lick his wang as much.

Now the past week, I noticed he's been horny. He tries to hump people when we say hi, or at least people he really likes, especially females. This is a new behavior.

2 days ago, he had another moment of incontinence. Then today, I noticed this morning swelling at the base of his penis, almost the size of a golf ball, that promptly went down after peeing. His penis will sheath. It does not come out often, but I also noticed when it is sheathed, it seems harder than usual, like he's still erect in there. There maybe some penis discoloration as well when it does come out, the tip seems slightly redder.

I'm asking if I should be worried, if it's an emergency/how soon do I need to get him to a vet, and anything I can do at home to alleviate it, if there is an issue?

He's acting normal outside the humping. He's eating, drinking, and exercising like he does (he's an athlete). He's peeing normal, he pees often/marks his territory. I don't think there's discomfort when he pees, but sometimes he does take slightly longer to get set up, (sniff, figure out what he wants to do, then goes). I'm not sure if it's bothering him or not.