What happen if you have high createnine?

Depends on context: Creatinine varies with both muscularity and kidney function. I'm fairly muscular and run creatinine 1.4 or so; when i was lifting every day it was 1.6. This can get you sent to the nephrologist nowadays with the fad for "estimating gfr" without looking at the person. If your creatinine is higher than that, it might be worth following up on other kidney function parameters.

Marker: Serum creatinine is a marker of kidney function--i.e. by itself it may not be deleterious to your health but it is a sign that shows that the filtering function of your kidneys are not adequate.