Why do i get canker sores on my tongue instead of a blister on my lip? i have herpes simplex 1

Different animals...: Canker sores aren't to be confused with cold sores (which result from herpes virus). Canker sores are not viral, and they are not infectious - they are similar to other immune type reactions, such as dermatitis, etc, and are frequently related to stress (local or systemic). The lesion on your lip would more likely be a cold sore, and your tongue is a more typical place to get a canker sore.

Different Causes: Hsv & aphthous ulcers can both benefit from in-office laser therapy (takes less than 5 minutes and significantly reduces pain and length of the presence of the lesions. Hsv episodes can be reduced and on occasion & "prevented" with a daily Valtrex (valacyclovir) regimen. Aphthous ulcers, unless you are lucky to have pinpointed what cause yours to surface more readily, there is not a med that will prevent onset.