Yes, bathe her in a mild shampoo, but also use ResiCort leave on lotion / conditioner. this is made by Virbac and can be easily found in pet stores or your vet can order it. it has 1% hydrocortisone and will really help!
most likely your dog had a hypersensitive reaction to something they used. be sure to alert them so they don't use those products on her again.
She may simply be allergic to the groomers shampoo and/or cream rinse. Please try bathing her with a hypoallergenic shampoo such as fragrance free baby shampoo or castile shampoo (avoid the eyes). Please dry her completely with a blow dryer before letting her go out. You may have to bathe her multiple times to remove the allergens. Please also give her fish oils containing Omega 3 Fatty acids. Fish oils can be purchased over the counter at most grocery stores and health food stores.
Other possibilities include contracting scabies, fleas, or other ectoparasites from the groomers; or, she could allergic to something in the environment or has become allergic to some ingredient in her food, and the itching post grooming is just coincidental.
If the bathing and the fish oils are ineffective please take her to the vet's for evaluation.