If i have lost a small piece of my gums through rugby, what should i do? will it grow back on it's own?

Gingival Lesions: It sounds like you may have bit your lip during contact, or another piece of your oral tissues if you were wearing a mouth guard while you were playing. This should grow back within a few days to a week. Best advice is to keep the area as clean as possible and rinse often throughout the day with warm salt water rinses to reduce any swelling.

Gums: This is impossible to say without a visual examination and more information. See your dentist for an examination, diagnosis and possible treatment.

Lost gum?: Some do and some don't. It really depends upon where you lost the gum tissue and how the injury is handled. It's best to see your dentist or a periodontist right away for a one on one clinical examination and consultation. Better to be safe than sorry.