After a FUE hairtransplant: can Iodine or other antiseptics do harm to the recipient area? 5 days post op.

It is best to contact your doctor about post operative care and instructions since each doctor has a different regimen.If you followed your doctor's advice then it should be fine.

Iodine as a antiseptic can not do harm to the grafts or has any effect on the growth rate after 5 days  of surgery .

It is unusual to use topical antiseptics after a transplant.  The way I read your question, you had concerns about the appearance of your scalp and after seeing photos your surgeon suggested the iodine.  The grafts are most likely fine by day five, though certain types of iodine solution or cream can irritate your skin.  If you choose not to follow your surgeon's advice, call back, explain your concerns and ask for an alternative.  Ideally you should be seen in person.