Ulcerate
/ˈʌlsəreɪt/
Definition 1 of 2
Pro Tip 1/3Medical Condition
Use 'ulcerate' when describing the process of an area on the body forming ulcers. 
After months of neglect, the skin on his arm began to ulcerate.
Pro Tip 2/3Negative Development
'Ulcerate' implies a negative progression in health or condition, often due to neglect or disease. 
The patient's wounds started to ulcerate after being untreated.
Pro Tip 3/3Associated Pain
Ulceration typically involves pain or discomfort, making it a sensitive topic. 
She winced as the sore spots on her feet began to ulcerate.