This is a study of participants with a diagnosis of migraine who completed another clinical trial NCT02163993. The participants received either LY2951742 or placebo. This study NCT02766517 will evaluate how certain biomarkers may be related to the participant's response in study NCT02163993. The study will last about five days.

Inclusion Criteria:

• Participants with migraine who have previously participated in study NTC02163993 and received one of the selected doses of galcanezumab or placebo
• Have suitable skin characteristics for the dermal capsaicin challenge

Exclusion Criteria:

• Have a history of significant allergies, in particular to ethanol or sensitivity to the fruits of capsicum plants (for example, chili peppers)
• Have eczema, scleroderma, psoriasis, dermatitis, keloids, tumors, ulcers, burns, flaps, or grafts on their forearm or other abnormality of the skin which may interfere with the study assessments
• Cannot avoid excess tanning (any exposure to sunlight or a tanning bed which would cause a sunburn reaction) throughout the study and cannot cover forearms for 24 hours prior to each treatment period
• Have excessive hair growth on the volar surface of the forearm or participants currently using lotions, oils, depilatory preparations, or other topical treatments on a regular basis which cannot be discontinued for the duration of the study; has used any topical treatments within 7 days of the start of the study

All randomized participants.

Day 1 to Day 3