Hot spot (?) On my dog. Maybe infected.

(Photos attached, warning; it's gross.)

This is Rocco, he's about to be ten and he's basically my whole life and the only reason I'm alive lol. I don't want any comments on his weight. He's about to be ten years old and had joint issues so he can't excsresize much. Hes fed once a day.

So, three days ago my sibling noticed the spot being small on his neck, I guess she figured it was just a scab from playing or something, but when I ot home 2 days ago and It was about half of what it is currently.

I cleaned it and wrapped it but when I woke up it was worse, and I've been doing my best to keep an eye on him to stop him from scratching but it just keeps getting worse, and on top of that he licks his paws when he's stressed or anxious, so he's started developing a small one on one of his paws I have to watch.

I'm doing all I can at home but idek what to do rn. I'm so worried about this. I'm trying to figure out the vet but I'm a minor for another month, and we can't afford it. My friend offered to help pay but idek how that's gonna work with my ma. What's really stressing me is my last senior dog who started getting spots like these died not long after, in December, right before Christmas. (More reasons to hate winter.) And I'm scared. I can't lose my dog.

I'm pretty positive it's infected. It doesn't just smell like a wound it stinks. Bad. I've had to strip all my bed sheets and the blanket I had on his bed cause this spot just won't stop oozing and bleeding.