The chlorophyll breaks down making the green disappear and the orange yellow or red become visible
        
             
        
        
        
I think it is stage 2
At stage two, the skin breaks open, wears away, or forms an ulcer, which is usually tender and painful. The sore expands into deeper layers of the skin. It may appear as a scrape, blister, or a shallow crater in the skin. At times this stage looks like a blister filled with clear liquid. Also at this stage some skin may be damaged beyond repair or may die.
        
             
        
        
        
An isotope of any element is the same, with a variation in the neutrons of the nucleus.
The mass number change but the atomic number doesn't.
In this case, protium, deuterium, and tritium are all hydrogen isotopes.
Protium is 1H or Hydrogen-1 is without neutrons.
Deuterium is 2H  or Hydrogen-2 has one neutron.
Tritium is 3H or Hydrogen-3 has two neutrons.