Your scalp problem could be a medical issue that requires medical treatment. I recommend you should pay a visit to a dermatologist, who is a skin expert. They can detect the condition and recommend the medications or treatment option that should be taken. Avoid using any harsh chemicals on your scalp until you have been to a doctor.
 

From what you are telling me, a cat must have bitten you. And even though it didn't bleed, you saw a burning sensation and a red dot after the event. This is a possible result of bacteria from the cat's mouth. It is important to wash the area with soap and water. Check for any swelling, pain, or redness. If you see anything out of the ordinary, don't hesitate to see a doctor.

It is not recommended to go to a solarium before your MRI scan, which is a tanning bed that is more powerful than a normal one. The rays from the solarium can affect how clear the scan will be sometimes. It’s like taking a picture with a dirty lens – things might not turn out sharp. If you are worried about anything, you should avoid the solarium and speak to your doctor about any further concerns.

It is not unusual for the untreated cut marks to turn into scars. Maybe the diluted glycerine solution will not be sufficient to help. You can consider adding some aloe vera gel to speed up the healing. Ensure the cut area is cleansed and well moisturized to let nature do the rest of the healing.