Question:
Is it permitted to cut mustache during sefira
Answer:
Normally not, but if it disturbs your eating it is permitted, The reason for this is that we find that one may cut his beard etc. during the nine days, if it disturbs his eating, and sefira is not more stringent that the nine days.
Sources:
O:CH 551-13, Piskei Teshuvos 493-7.