What does a high lymphocyte count in small intestines mean?

Unclear: Lymphocyte "count" usually refers to blood. In tissues lymphocytes can be benign and due to inflammation or autoimmune disease, but can also be malignant (not as common, especially in someone so young). A pathologist should be working on this for you to determine the meaning of the finding.

Small bowel disease: Lymphocytes are part of the body's defense system-- usually they are recruited to fight an infection or prevent one from taking hold. It sounds like you were given a biopsy report on a small bowel sample? If there were lymphocytes there, probably this was in response to something- although without other information it's hard to say what. Generally we will call this 'nonspecific' if there's no info