I had smart lipo 3 and a half weeks ago. Is my incision site infected? (Photo)

It looks as if the port site is still healing, likely was burned or irritated during the procedure..  A silicone based scar gel is with growth factors and aquaphor ointment are best to promote the healing.  Dr. Emer.

It appears that you've experienced skin erosion, possibly due to a burn, but it doesn't appear infected. Be careful to prevent infection by keeping the area clean and wiping away debris regularly. Your surgeon should give you specific instructions and prescribe oral antibiotics to prevent infection. If you have had staph or other aggressive skin infections in the past, your condition warrants more intense management.

Sorry to hear you are having a healing issue. This looks like an area that suffered a minor burn, which is not uncommon with liposuction of any type when the instrument rubs and irritates the skin many times. This will heal quite well, but sometimes needs a simple procedure to remove the old scar and re-close it. I would usually wait a few months before doing that. Best wishes on your recovery.