10 year old refusing to go outside due to bugs

HI guys, I'm new to the NAS, my son has ASD and ADHD.  He recently had an encounter with a wasp in his trampoline that freaked him out and is now terrified to go outside in case a fly or wasp comes near him, he's even refused to pick up stones (which he used to love collecting) in case there was a bug on it.  IT hasn't helped at a mozzie seems to have taken a liking to him and his thigh is covered in bites.  Any advice on how to deal with this would be greatly appreciated, my husband and I just don't know how to handle this new development.

We had just got him coming outside with me more and off his devises but this has set him back a long way :(