What are the physical effects of stopping dialysis?

Kidney dialysis: Harmful effects of not having dialysis include accumulation of harmful products such as urea and creatinine (uremia). This may eventuate into death.

Multiple things: You can become uremic leading to pericarditis, nauseas/vomiting, altered mental status, and comatose. Also you can and likely will become hyperkalemia (increase in your potassium) and if this persist you will die from a cardiac arrthymia. Also you will have itching from increased phosphate. It's best not to missed dialysis.