Will Numbness Go Away After a Cut to the Forehead?

No!  The sensation normally comes back within the first year. That being said, patience is a virtue...  Although I am the least patient person out there - easy for me to say...Best of luck!

It is normal to have some numbness at the site of trauma (cut) that will eventually heal and the numbness go away. However, if the cut involved a cut in any sensory nerve, the numbness will be permanent unless the nerve is repaired.
Edema of the trauma site can cause some change in forehead muscle dynamics, however if you cannot move the brow at all, you may have transected the frontalis nerve!! Exploration and repair of the nerve would be mandatory to minimize any permanent paralysis of the frontal muscles of the forehead.
Hope this helps,
Ali Rıza Öreroğlu, MD FEBOPRASEuropean and Turkish Board Certified Aesthetic, Plastic and Reconstructive SurgeonIstanbul, Turkey

Facial
lacerations are extremely common and may be associated with injuries to the
underlying muscles and nerves. For this reason, it’s not unusual for patients
to note numbness and muscle weakness. This may occur for a variety of reasons
including direct damage to the muscle, transection of the nerves or bruising of
the nerves. In addition, these injuries can cause significant swelling which
can also adversely impact muscle and nerve function.In the vast majority of cases,
muscle weakness and numbness resolve in 3 to 4 months following injury. In some
cases resolutions may take up to a year. In rare cases these changes may be
permanent, but this would be unusual. If you’re concerned about numbness
following this type of injury, consultation with a board certified plastic
surgeon is appropriate. This surgeon should be able to address your concerns
and alleviate your anxiety.

It is common for numbness to occur after surgery. It can take a few weeks for numbness to go away, but sometimes it may take up to a year. Nerve regeneration will slowly occur over this time, allowing you to have sensation again, and this is associated with tingling.

Hello! Thank you for your question! Numbness after any surgical
procedure is expected for several weeks to months following. As the
nerves to the area are traumatized and will then experience a temporary
neuropraxia, a transient loss of nerve conduction. This usually
resolves over the next 6-12 weeks, but depending on the procedure
performed, sometimes much longer. Typically this should resolve by 1
year. As it goes past this date, the likelihood of the sensation
returning is small. However, it can take up to 2 years. If no return
from there, it is unlikely to return. It should be discussed that
persistent sensory changes may develop following any surgical
procedure. The usual signs of the nerves regenerating and neuropraxia
resolving is itching, followed by a burning sensation and then
occasional sharp, shock-like pains. These will be normal to experience,
and actually a promising sign. Usually, normal sensation returns, but
is is also possible to have decreased sensation or even increased
sensation to the areas affected. Re-educating nerves postoperatively is
often helpful and will allow proper instruction for the affected
sensory nerves - methods include using different textures to the
affected areas when showering, bathing, applying lotion, etc. If
bothersome, there are some medications that may be helpful, including
Neurontin for pain for hypersensitivity. You can try various textures
such as washcloths, loofahs, cotton sheets, etc. Massaging the areas is
also beneficial for the incision to make the finest scar possible. The
last place to regain the sensation will be directly adjacent to the
incision/scar as the nerves will make its way from the periphery to this
location. If continual pain arises, evaluation is warranted. After
ruling out other causes, one rare explanation may be that a neuroma has
developed and may require surgical excision. This is very unlikely
unless a large sensory nerve has been transected inadvertently during
the procedure. Hope that this helps! Best wishes!