It may not be chilblains. It sounds more like gout, which can be aggrevated by UT. The body hydolyzes uric acid and excretes it through the urine. So ingesting the urine can increase uric acid load.
Nettle leaf and juniper berry are both great for reducing uric acid load. Malic acid dissolves uric acid. This is the active component in cherry juice, which is commonly used to treat gout.