The way I usually do this is to build an array from the field.
$values = array();
if (get_field('field_1') {
$values[] = get_field('field_1');
}
if (get_field('field_2') {
$values[] = get_field('field_2');
}
if (get_field('field_3') {
$values[] = get_field('field_3');
}
Then I use implode do display
if (!empty($values)) {
echo implode(', ', $values);
}