Hand and finger licking in need of some advice.

Hi I am quite new to this, I have a 10 year old son who has learning disabilities and is awaiting assessment for Autism, he has always had a thing about putting his fingers in his mouth to the point that fingers on one hand look different to those on the other. Over the last few months this has been getting worse and he has been licking the palm of his hand also, he doesn’t appear to realise he is doing this. Along with this came a strange breathing thing where every so often he does a sharp intake of breath with a jump. I’m worried about how this may affect his lungs and also the germs he is going to pick up. We’ve spoken about it but as mentioned before he doesn’t realise he is doing this, he has started to feel different to other kids at school and I’m also worried they are going to start noticing him doing this too. Any advice would be greatly appreciated as we are really struggling as it is at the moment. Thank you.