Hey there skatercooper. Welcome to the site. I'm glad you found us.

Here are some thoughts to the questions you asked:
Why is it getting worse?
Well, as we get older, our brain and body goes through changes. When you have SPD, these developmental changes can often lead to issues. Some problems can get much worse. Some can get better, although that's unlikely unless you're getting good treatment, like through occupational therapy.

How can you make it stop?
Well, I'm sorry to say this man, but SPD is generally something that is here to stay. It's not easy to accept that. It really isn't. I sometimes struggle with that myself. However, if you get OT and continue to work on things and keep your sensory needs in mind, things really can improve. I'm in better shape now than I was before. It just took time, work, and help. It's possible and can be done.

Why do you like to touch Playdoh so much?
On this one, I would say you find it pleasant to the touch. Basically, it's giving you the tactile (touch) sensory information you need to help regulate. Whether it's making you more alert or calm is a question, but either way, it's helping your system organize. I know it sounds weird dude, but trust me, you are not the weirdest person here, LOL!

In fact, there are types of putties and stuff that they sell because a lot of people with SPD love the stuff. I liked it when I was a kid, and many of my SPD friends like to mess around with it still as adults. I encourage you to get more Playdoh and play with it more often, lol. It's safe, and even if your peers think it's weird, well it doesn't matter if it helps you feel better, in the end.