If it were to take place at the ideal age of around 18 months and physical damages were limited to local effects (oral absorption through the tissues of the mouth, for example, leading to saturation of the blood stream through the most direct method) then you could trigger very dramatic changes in stem cells that were catalyzing at that time to form the building blocks of a human being. Perhaps even causing major shifts of protein synthesis to alternates proven to be present by DNA sequencing and often developing from other forms of trauma or disturbances.
Commercial name is Drano. My aunt had left it out in a glass coke bottle mixed with water when my father came to visit and had forgotten about it. As an infant I crawled into the kitchen unsupervised and took a few sips. That night I was given the last rites at the hospital and was expected to die by morning. The doctor got it right when he said "It's for the best. Nothing human could have survived and the child would be horribly scarred beyond recognition had he survived. The result would have been a monster. No way could he have recovered from injuries like those he sustained without some sort of miracle."
Something connected to methylation switches on the ARNDT2 gene sets off a cascade that begins pulling genetic sequences for fundamental development from the archaic DRD chains. Once started, they begin to fall like dominos until they all run out. I suspect the body is saying "Something bad has happened to this kid who is currently running the Holocene candy-ass spearchucker model software. We may need to do a rollback and switch him to the original Ice Age supertank Model T version of hominids in order to prepare him for what appears to be a very rough environment he is growing up in."
Two years later I was glowing pink faced with health, built like a chimney of muscle and was bouncing off the walls of my doctor's office like Spiderman. He told my father ... "This is not the same child I examined originally." I had almost finished off the school library by the 2nd grade. My nasal pitch, rapid delivery, nonstop verbal information blitzkrieg and strange intonation often left people feeling they were talking to a creature from another world by the time I was 7 years old. No need to tell me how Neanderthals sounded when they spoke, National Geographic. I already know how Neanderthals sounded.
The scarring from the chemical burns left me a hideous monstrosity somewhere between the Elephant Man and the Amazing Colossal Beast. You can see here why I never go outdoors in daylight.
