Im having alot of radiation exposure from ct's. in the past 2 years i will have had 2 head ct's and 2 sinus ct's. how likely am i to get cancer from this, especially as this are relatively close to each other?

Cancer risks are right about zero.

The increase in risk is too low to be measurable. You can reduce your risk of cancer by adopting healthy habits: Eat a mostly vegetarian diet, avoid alcohol, tobacco and street drugs, avoid excessive exposure to sun, maintain healthy weight, get HPV vaccine, exercise 30 minutes each day, drink enough water so your urine is mostly colorless. Wish you good health!