10 days after TCA CROSS treatment is definitely too short a time to see significant improvement and you are right that you would need 4-8 weeks to appreciate the full effects as it takes time for the fibrosis and collagen stimulation to occur.
Also, depending on the depth and type of your acne scars, it may take a few sessions before you can see significant improvement. Also, you may need other adjunct treatments like subcision to improve the deep and tethered scars, and fillers for the very atrophic ones.
Other factors that can influence how an individual responds to a particular treatment will be:
1. Skin texture - dry skin may have a different healing/regeneration time compared to oily skin
2. Skin tone and quality - With increasing age, there is lesser collagen and elastin in the skin and the skin regeneration time is longer
3. Genetics
4. Sun exposure - UV rays increase skin collagen breakdown and induce the accumlation of abnormal elastin
5. Smoking - The multitude of toxins and chemicals present in cigarettes cause damage to skin collagen and elastin and hence can affect the rate of skin regeneration
6. Diet - A high sugar diet results in high blood sugar levels, resulting in formation of Advanced Glycation End products(AGEs) which damage proteins like collagen.
These factors basically affect the amount and quality of collagen in the skin, as well as the regenerative capacity of the skin. Hope that it answers your query!
