[JRTJH]

^^^^ What he said. The 14 ga wire on the 15 amp side is currently (pun intended) not protected. A 20 amp breaker on that circuit will allow 20 amps through a wire that is only rated for 15 amps. That could lead to overheating and a fire or it could lead to damaged wire from the overheating which may cause it to not be able to carry the total of 15 amps in the future.

I'd limit use of that circuit until you can locate the proper 15/20 amp breaker.

Are you in danger? Only if you overload that circuit, otherwise, the wire doesn't know that an over-rated circuit breaker is installed. But, if you overload the circuit, you can do some "critical damage" including burning down your trailer.

Change it out at your first opportunity. This is not a 'little thing" if you overload the circuit, even accidentally......