Is it infected? (Photo)

This drain site looks like it has been infected prior to the drain being removed. It looks like it's healing, but it has some necrotic or dead tissue. You should follow up with your surgeon to clean the tissue to help it heal faster. 

Try to keep it dry as much as possible, I suggest you follow up with your PS at this point every surgeon has different post op care instructions.

Dear Laura028,this type of wound is not uncommon after tummy tuck. It is usually caused by a stitch. I would suggest you to follow your surgeon's instructions and keep your wound clean and covered. It can take few weeks or months for wound to fully heal. Daniel Barrett, MD, MHA, MS 
Certified, American Board of Plastic Surgery  
Member, Am. Society of Plastic Surgery

Hello Laura028 - Based on your photos you should follow up with your plastic surgeon. It could be nothing but an in person exam is best. 

Hi dear,

 Thanks for the questions.

I recommend you to follow up with your plastic surgeon, probably is not something to worry about but is better to prevent.
 I hope this advice helps you. Best wishes.-

Manuel Belén, Board Certified Plastic Surgeon