I would only give IM antiBs (Alamycin/Terramycin) for persistent lameness caused by smelly footrot, not as a 'just in case', which is where antibiotic resistance begins - there may be no infection there, or the infection there is may not be susceptible to the AntiB you have. If there is anything like redness between the cleats and so on, spray with Terramycin foot spray If you suspect a joint involvement then feel with your hands to detect any heat and if that is present then consult your vet (by phone, or take the sheep to the surgery) for advice on which antiB is appropriate. It always makes less of an impact on your wallet to take the sheep to the vet, rather than getting a home visit.
If there is bruising, a strained ligament or twisted leg then just give her time to recover- at least a week then seek advice if she is no better.