I've just been recently diagnosed with an under active Thyroid. I'd been going to the doctors with recurring mouth ulcers for over 2 years, but they were getting really bad and not healing, I was wondering if anyone else had this symptom. I'd had loads of blood tests last year, including my Thyroid but nothing showed up, but I'm sure I've been getting a lot of these symptoms for well over 2 years, does it not always show up? It was just a routine health check, that notice my cholesterol levels had gone up slightly and they were going to check my Thyroid and then the penny dropped. I went online and I had 8 out 10 of the symptoms. I'd been going back and forth to the doctors with different symptoms but not 1 doctor linked them together, very frustrating because now the symptoms are quite bad. I was wondering how long before I start feeling better?