Yes, excess mucous can be a sign of peanut allergy. Peanut allergy can also cause worsening of asthma.
This allergy is more prevalent in children than adults and you might want to avoid peanut butter for a few years.
I am not sure if it's an allergy because if it were an allergy, you would have a more acute and serious reaction. It could be a sensitivity. Head to the doctor and find out.