If you can you should go up to a 28c or even 32c tire. The former being a big improvement over your 23c the latter being even better, and I can personally testify that your speed will not be affected much if at all. If anything it will improve over less smooth surfaces. I am surprised you are able to ride on those skinnies at all with your condition. Wear padded riding gloves with padded tape or grips. Good luck to you sir. Any hand/wrist pain/discomfort can be a huge detriment toward riding.