Is he being aggressive?

Hi i've had my netherland dwarf nearly a week. He belonged to my niece. He is 9 months old and not neutered. I could easily pick him up until last night when i put on his spot on flea treatment. Since then hes stomped when i've gone near his cage, shook and bared his teeth. Have you any advice on what i can do to regain his trust? Totally new to keeping rabbits
Thanks in advance

Where did you pick him up from yesterday, was it from his cage or outside it?

He was in his pen. I applied the treatment whilst he was in there and he started darting all over the place. I've obviously scared him bless him. My husband picked him up once he'd calmed down a bit and out him back in his cage because he would'nt let me touch him