Tyre pressure problem

Hello together, I try to describe this as detailed as possible as it can be done in such a case. I found out about 2 weeks ago that my rear tire of my SR50 was a bit flat (at that time I didn’t have a “mobile compressor” at hand). Since I had an appointment and I knew that there was a tank coming on the way, I wanted to pump air there. Only on the way there the driving behavior became more and more sponged until I found out that the So back home. Today I got to go on troubleshooting. With flush water I then found out that at the transition from rim to tires all around bubbles form (left). The tire itself did not show any damage. Now my question would be: By driving on “plate” it can be that the rubber has spread there and there is a possibility to regulate it itself? Tyre technically I have absolutely no Ahnun at this point. g.