These symptoms may point to mild nutrient malabsorption and hormonal fluctuations or vitamin deficiencies. Sticky, foul-smelling stools often suggest difficulty digesting fats. The facial pigmentation is likely melasma, which is very common and harmless. For your digestion, a doctor might suggest dietary adjustments or digestive enzyme supplements. For your skin, daily broad-spectrum sunscreen and topical treatments like azelaic acid or vitamin C can help fade the dark spots. Please consult a physician for simple stool and blood tests to identify the exact cause and get a tailored treatment plan. These symptoms are highly manageable, so try not to worry.