Complex sentence: Using a local anesthetic to numb the skin may not be necessary since a thin needle is used for the biopsy Recieving an injection to prevent pain from the biopsy may be more painful than the biopsy itself.
Split into simpler sentences: Using a local anesthetic to numb the skin may not be necessary since a thin needle is used for the biopsy. Receiving an injection to prevent pain from the biopsy may be more painful than the biopsy itself.