Is there a way to "save" curdled custard? Can I try to churn it or do I have to throw it away and start frtart deom scratch?

Kind of depends on how badly curdled we are talking about. If you have a blender, food processor, or hand held immersion blender stick - you can use one to help reduce the mixture to a somewhat smoother blended mixture. You can then pour it through a fine sieve, or not - your choice depending on how grainy it is. Then freeze it. It might not be as baby bun smooth, if you are a delicate palate person - but for most of us mere mortals it will be just fine.