dog groomers?

hello! for some background i have an 11 month old cocker spaniel. i got him from a puppy mill situation which i am not proud of but i am now much more educated and suffering from the consequences! he is people reactive and has bitten a vet tech before. he also has some separation anxiety. ive been grooming him at home as im very nervous to send him to someone but its all just so much and i really dont know how to get better/get him good enough to go into the groomers. he also is quite sensitive to tools like clippers or scissors and hates the dryer. does anyone have any advice on getting him used to tools and to help him w the groomers? or anyone else who does at home grooming have any tips on how to get better?