It is not uncommon to see significant post op periorbital edema and ecchymoses following forehead surgery. Regardless, I would suggest discussing with a Board Certified Dermatologist with expertise in Mohs surgery.
It is within normal limits to have bruising or eyelid swelling up to a few days after forehead surgery.
The main thing to exclude is a hematoma which is typically a tender "lump" and represents a larger collection of blood (different than normal swelling and bruising). Hematoma should be seen and sometimes needs treatment (drainage).
If the surgical site is not tender and there is no tender lump and if the swelling is getting better over a few days that would suggest it is less likely a hematoma.
Most reliable way to distinguish is to see the MD who did the surgery.
It is normal to get some swelling and bruising around the eyelid after Mohs surgery. I would recommend contacting your Mohs surgeon because they will likely want to see you or speak to you over the phone to make sure it isn't something more than bruising, such as a hematoma.
Please discuss with your Mohs surgeon and/or plastic surgeon if one was involved in your reconstruction. Simple bruising resolve within 7-10 days but it sounds like you might have a hematoma which might require further treatment. It will definitely take several weeks to resolve regardless. I hope this information is helpful for you.
Stephen Weber MD, FACS
Denver Facial Plastic Surgeon
This is something that should be discussed with the physician who performed your procedure, and I'm surprised wasn't already discussed with you. Any surgery of the forehead causes swelling and bruising around the eyes as the edema and blood flow down with gravity and pool around the eyes. But without a photo we cannot give you a definitive diagnosis and you should seek the advice of that doctor who treated you. I wish you the best of luck, Dr. Emer.