Headaches and Lump on Temple

[twoplustwo]

I am a 21 year old male. I recently had some trauma to my right temple. I had no pain in the area untill 4 days later, I had flu like symptoms for 2 days and started to get headaches (pressure and tension in both of my temples). I also noticed a small pulsing lump in the area. (I rarely had headaches before this)

After 3 days with terrible headaches I visited the ER and had blood work and a CT scan done. Both came back negative. The doctor initially thought that it was bruising realted to the trauma but had me return the next day for an ultrasound.

The doctors told me that the ultrasound showed damage to an artery in my temple. (Could a trauma to the artery show simmilar symptoms to temporal arteritis?)
I was also told that being so young, temporal arteritis was not the cause of the lump and my headaches. That I need not worry about this effecting my vision.

A week after the onset of my symptoms, the headaches are no longer as severe, though I still have slight pain in my right temple, and feel pressure on them from time to time. The artery is still large and visible on the side of my head.

I am wondering if I should have a biopsy done on the artery.
At my age is there even a remote chance that temporal arteritis is the cause of this? Would the possibility of me having GCA come back in blood tests? (I have no previous illnesses that relate to GCA)

I have not had any problems with vision, but if GCA is a posibility I would like to be safe and have a biopsy done (this was not recommended by the doctor in the ER)

It will be atleast a week before I can get an appointment with my doctor, and then more time to have a visit for a biopsy if needed. I understand that time for treatment is an important factor with GCA, would 3 weeks from the onset of symptoms be too long to wait?

Thanks for your time.