I agree to get to a vet as soon as you can. The signs are showing that means your pup needs treatment.

Nothing is more than 90% effective for ticks, so checking daily is the best thing. Frontline spray is the only thing you can use in a pup that is under 12 weeks of age, so you have done the best thing. Once the toxin is in the central nervous system, its important to get to a vet ASAP. goodluck!

ETA: yes proban is a preventative measure, there is only one thing to treat it and that is anti serum that a vet has to give. Proban has to be used every 48 hours, and TBH is hard to get people to do right, but it is extremely effective!
ETA2: I'm a vet nurse as well