I had a slow leak in my back passenger tire?

I had a slow leak in my back passenger tire. It was losing approximately 3-4 PSI per day. The outdoor temperature has been cooler, but the other tires are not losing at the same rate.

I decided to use Slime tire sealant on my own. I followed the directions by making sure the valve is positioned at the top half of the tire, taking out the valve core, fully deflating the tire, attempting to put Slime in (very little, if any got in), and replacing the valve core. The final steps included re-inflating the tire and driving for a bit. However, when I tried to re-inflate no air would go in. My small compressor would start and stop as if the tire was full.

I also tried a stronger compressor, as well as attempting with the car jacked up, and attempting without the valve in the tire. No air will go back in.

I am at a loss for what else I can do before taking the car into a shop. Any help would be appreciated.