I can understand your concern for lipoma and prevention by lemon juice and green tea help to prevent new lipoma.
After analyzing your query I can make out that you want to use by lemon juice and green tea help to prevent new lipoma. To tell you regarding lipoma prevention- there is no particular oral treatment or treatment by mouth by which the lipoma can be prevented. Lipomas
are forming due to deposition of extra fatty tissue. These never impose or never cause any problem.
The only method of treatment of lipoma is by removal of the existing lipoma by surgery. You can meet a dermatologist
for best guidance.