Dynamically cross-linked polymer networks have promising potential to serve as self-healing materials, but this is often limited to occur at elevated temperature. We overcome this limitation by refinement of an earlier approach to synthesize dynamically cross-linked polydimethylsiloxane networks such to show stress relaxation and self-healing at room temperature on short time scales, which we probe by oscillatory shear rheology and piercing experiments. Our studies reveal a direct correlation between the amount of anionic groups in the polymer networks and their stress-relaxation and self-healing rates, allowing these materials to be designed in a rational fashion.