Hello and welcome to the forum. We appreciate your question. Elevated lipase can be associated with gastroenteritis which you may have had based on nausea you describe. If your stomach lining is irritated, you can have elevated lipase. https://www.medicalnewstoday.com/articles/322201.php You could also have your symptoms and pancreatitis and have elevated lipase. Sometimes a bland diet will help such as the brat diet. This is banana, rice, applesauce, and toast. Lipase can stay elevated for a couple of weeks after a bout of gastroenteritis or pancreatitis. How long has it been?
In order to prevent the rise of lipase, you should pay attention to your diet in daily life, do not eat fried foods, also do not eat foods with high fat content. It is best to eat some fresh fruits and vegetables, and you can change your eating habits according to the specific situation.
Elevated lipase, especially when more than 3x the reference range, is suspicious for pancreatitis (difficult to see on ultrasound). Differential diagnosis of pancreatic cyst includes pseudocyst (in the setting of pancreatitis), sidebranch IPMN, or serous or mucinous cystic neoplasm. MRI/MRCP, as suggested by your GI doc, can help to further characterize.