Spike in two minds about Henry (5)
I believe the answer is:
thorn
'spike' is the definition.
(I've seen this before)
'in two minds about henry' is the wordplay.
'in two minds' becomes 'torn' (both can mean indecisive).
'about' indicates putting letters inside.
'henry' becomes 'H' (symbol for the unit of electrical inductance).
'torn' going around 'h' is 'THORN'.
(Other definitions for thorn that I've seen before include "eg Prickle on rose" , "Sharp-pointed stem-tip" , "Sharp point; runic character" , "Sharp point on plant" , "Cause of grief" .)